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Chevy Suburban and Tahoe AC and Heater Problems

13567

Comments

  • esther08esther08 Member Posts: 3
    I have the same problem, did you ever find out how to fix it?
  • natalenatale Member Posts: 5
    Arrie,
    Good Morning! Thanks for getting back to me. Yes when i shut everything down, Heat/Ac and drive the truck it runs normally, no sound no nothing. I am going to try and charge the system as you suggested. I will let you know how it turns out. Thanks for the detailed instructions it was very helpful. I hope this works. I would really have to go through changing the compressor and having to spend $800.00.

    Best Regards,
    Natale
  • arriearrie Member Posts: 312
    Yes,

    please post back wether it helps or not. This way it helps others in this forum too.

    Thanks,

    Arrie
  • waltherchicwaltherchic Member Posts: 2
    I have the same issue, just started on my 2002 Suburban 2500. The lower AC belt broke and the shop replaced it. Immediately, we started hearing a rattling noise from the AC when we stepped on the gas. Brought it back, said the tensioner was broken. They agreed to replace it because this was the 3rd time we'd had to come back in for stupid issues. They replaced the tensioner and I went out, started the truck, turned on the AC and hit the gas and the noise started up again. Two guys from the shop were right there. They checked and they said the tensioner broke.

    I looked up the service bulletins on this truck and 01139B is the exact issue. Doing some more research, I found that it's a down problem where slugs of liquid refrigerant are being pushed into the compressor. They clog a tube which then blows the tensioner. Ugh.

    I'm pissed because the AC kicks just fine. It's cold and the fan works. It's just noisy as all getout and sounds like the belt is going to go flying. This wasn't happening prior to them replacing the belt or the tensioner. I'm wondering if they could have reinstalled something wrong and caused the problem.

    The shop quoted me $1300 to replace the compressor, tube, tensioner, etc. I just don't want to put that money into this truck right now. I'm having a hard time believing that this is the issue, if it was, it would have done this before the new belt. Right?
  • arriearrie Member Posts: 312
    You say ...A/C kicks just fine...why do they want to replace the compressor then?

    If the issue is that ...slugs of liquid refrigerant are being pushed into the compressor... then the fix for that is very simple...let some refrigerant out from the system. This is very easy to do. Just have a refrigerant charge hose connected to the low pressure side service port and let some refrigerant out. Have hose spraying in a container or something covering it with paper towels or something else so the refrigerant does not get on painted surfaces. It could hurt the paint.

    If you let out big amount of refrigerant you might want to add an oil charge after that to make sure you don't drain the system from lubricating oil that the compressor needs.

    If your compressor runs well and works, i.e. cools the air then if the compressor itself is quiet there is no need to replace it. And if it makes noise oil charge can fix that too.

    The tensioner breaking right after new one is installed does not make sense. The tensioner simply is a pulley mounted in the end of an arm that is spring loaded against the belt. The way tensioner normally fails is that the bearing of the tensioner pulley wears out. Very seldom the spring breaks but is possible.

    Almost sounds like the shop that fixed your tensioner installed the old broken tensioner back in and then tell you you need to replace $1300 worth of parts to fix it. I say this because I see so much scam amongst the car repair shops and it is getting much worse in a hurry. And it seems dealer service shops are amongst the worst ones with this.

    I don't know if you are a hands-on person but a belt tensioner is not very difficult to fix/replace. In these vehicles I think you need to get under the car to do it though so you need to have vehicle elevated on ramps or at shop.

    Here are steps I would take before costly compressor replacement:

    1. Go to car parts store and buy A/C charging hose, pressure gauge, 2 cans of oil charge and 1 can of refrigerant. All this for about $30-$35.

    2. Start car and turn A/C ON at max cooling.

    3. Let run for a few minutes and then connect pressure gauge to the low pressure side service port. Record pressure reading. The pressure is ambient temperature dependent but the pressure gauge should have an area marked with green where the pressure reading should be at.
    4. Use one of the oil charges, i.e. charge the A/C system with oil.
    5. See if the oil charge helps any. One of the ways the noise from tensioner occurs is that the compressor could be hard to turn, i.e. low oil lubrication could cause the compressor run a little bit tight and at each piston compression stroke could cause drive belt tension change and start bouncing the tensioner that then causes the noise.
    6. If problem does not get better let some refrigerant out. This would be necessary if slugs of liquid refrigerant enters in the compressor. No liquid should enter the compressor as liquids do not compress. Let out fairly big amount of refrigerant checking pressure at times and see if it helps. If the belt tensioner is broken you might need to have it fixed before you can definitely tell if your noise problem has improved but even with broken tensioner you should hear a difference.

    After letting all that refrigerant out add the other oil charge in the system to make sure you have enough oil charge in it. If you happen to drain the system low enough so that the cooling performance goes bad then use the can of refrigerant to re-charge the system to point where cooling is good again.

    If oil charge and lowering refrigerant level in the cooling system do not help you might be facing that $1300 repair cost. But, for making sure you are not spending all that money just because your compressor is running on low lubrication or the system is over charged (liquid entering compressor) the above explained less than $40 trouble shooting procedure might pay off.

    There is another lower than $1300 cost repair to try before replacing the compressor if the above explains oiling/charging does not help, the expansion valve replacement.

    Cooling system working principle is as follows: Compressor increases gas refrigerant pressure to a very high level. With this the temperature of the high pressure refrigerant also gets very high. When this high pressure and high temperature gas enters the condenser (at the radiator at front of car) it turns into liquid form when the heat is removed (air flow cools it down). Now at liquid form and still under high pressure the refrigerant flows thru expansion valve. This valve simply is a fixed size hole in the tubing and it separates (like the compressor) the high and low pressure sides of the cooling system. The liquid refrigerant turns in gas form after the expansion valve and causes cooling in the evaporator element, which the air is blown thru inside the car.

    If the orifice of the expansion valve would wear out and be too large it could let too much flow thru it and cause some liquid form refrigerant to appear in the low pressure side of the system.

    The expansion valve is very low coast item. I have bought 3 of them in the past for some older cars I had and the most expensive of them was $7 + tax. It could cost perhaps even $20 now. Anyway, the problem is not the cost of the part, it is the work to have it replaced because the whole A/C system must be drained. Expansion valve is located inside the A/C tubing right at the break point in line before that low pressure side service port. While A/C is running you can feel this in temperature of the line as the high pressure side of the expansion valve is hot while the low pressure side is cold.

    The problem with this work is not the replacement of the expansion valve. It is the re-charging the refrigerant because before that you need to vacuum the system. Vacuuming is necessary because air in the system causes poor performance as air is incondensible gas, i.e. when compressor compresses air it does go to high pressure with high temperature but it does not turn in liquid form in the condenser but remains in gas form and circulates back to compressor taking room from the refrigerant to be compressed. But, you could change the expansion valve and then take the car in an A/C shop just for vacuum and charge.

    Arrie
  • nflguynflguy Member Posts: 90
    Is there not anyone else with the same problem on a newer model Tahoe?

    Our 2007 Tahoe has fluctuating fan speed on the ac. It seems especially worse on the middle speed settings. I will be driving along (or sitting at an intersection) and the speed will suddenly go up or down for a few seconds. NOBODY else has this issue?

    I took it in twice to the dealer and each time they said the system was fine. I took it back a third time and they said the aspirator was bad. However the problem continues.
  • arriearrie Member Posts: 312
    Is it an automatic climate control system or is it manual?

    Automatic system does change fan speed according to temperature reading inside the vehicle.

    A sudden change in fan speed can happen for example if the driver's head is located too close to the air temperature "sampler" intake in the ceiling and suddenly changes distance to the sampler. Help for this issue is to set driver's seat lower so that head is not too close to the sampler intake at any time.

    Sounds weird but drivers head being too close to this small "speaker looking" air intake can change air temperature entering inside the tube where temperature is measured. This happened to me and I had to lower my seat down from where I first wanted to have it.

    Above assumes that the air temperature measurement is made to work the same way as in '04 Tahoe with automatic climate control.

    If your system is a manual climate control and has fixed fan speeds and fan speed suddenly changes you have an issue, which must be fan or fan speed controller related.

    Arrie
  • nflguynflguy Member Posts: 90
    I can have it set to manual or auto. We don't typically use the auto but when we do the same problems happen.

    This is a VERY frustrating problem. I'm likely to be out of warranty by the time next summer rolls around so I wanna get this fixed asap.

    They said nothing was wrong the first few times they checked it out. The problem got worse and worse until eventually the max air button would click off on it's own even though we were on manual setting. I brought it in again and they said the aspirator was bad (the thing above your head) so they replaced it. Now the max ac button no longer shuts off on it's own but the brief changes in fan speed have returned. I fear it's some kind of electrical issue with voltage problems on the blower resistor. The problem is that dealers rely on the vehicle computer system when deciding if replacing parts is needed. If there is a problem but the computer doesn't show it (via codes) then the dealer won't do anything to fix.
  • arriearrie Member Posts: 312
    Just wait until your warranty is gone and your dealer will find all sorts of issues to repair on your vehicle.

    GM is in so deep mess at the moment they cannot afford fixing vehicles on warranty unless they absolutely have to. Issue like yours, if not absolutely repeated at the dealer's service shop and you having witness with you will not be repaired on warranty but as your warranty goes out I can guarantee they will want to change all kinds of parts on it as it will be done on your dime.

    I had to trouble shoot and fix my car myself after the first about 2000 miles when fuel consumption went from 18+ MPG to 13 MPG on highway driving. Dealer claimed there was nothing wrong as there were no trouble codes in computer. I found all sorts of problems the intake manifold leak being the biggest one...and whole bunch of improper electrical connections on wire harnesses...

    Good luck with yours.

    Arrie
  • nflguynflguy Member Posts: 90
    What year Tahoe did you have the problem with???
  • arriearrie Member Posts: 312
    2004 LT,

    I have been buying "little used" 2 - 3 years old cars before as I am kind of a mechanic and fixing cars for me is easy unless it is a computer issue or something like that.

    After years saving money I finally was able to consider buying a new vehicle and it sounded so good not needing to work on it. It cost almost $40 000 to get my hands on this Tahoe LT and then all but trouble. And chevy dealer does not do anything to fix it.

    Tail pipe looks like it burns a gallon of oil between oil changes, but it did not and still does not burn any oil. It just sent unburned fuel thru tail pipe as engine was not working at the most effective way and biggest problem with this seemed to be intake manifold gasket leak. Believe or not but it has a lot to do with engine performance as leak changes MAP sensor reading, which is part of controlling ignition timing.

    Leaking intake manifold gasket also caused rough or jerking idle.

    I also soldered almost all wires to the pins at sensor harnesses. I believe the only one I have not done yet is the crank shaft position sensor wire harness and that is because it is not easy to get to. Starter motor has to be removed to gain access to it.

    My Tahoe works quite well now and I still get about 18 MPG with 77 MPH speed on highway. I have 94 000 miles on it.

    Last scare was coolant level dropping off but it seems to have fixed itself after I poured some Bar's leak fix in it.

    Arrie
  • nflguynflguy Member Posts: 90
    Finally last week they said there was a problem. They told me my aspirator was bad and that was causing the blower speed to vary and the max ac to shut off. That fix lasted one day.

    I dropped the tahoe off this morning and showed the tech guys how my ac fan speed will go up and down even when parked. They called and said they can't figure it out so they are gonna replace the control head. Well see if it works.
  • thomas40thomas40 Member Posts: 2
    I know exactly what your talking about. I bought our 2008 Tahoe in May. I have had it into the dealer six different times, due to the AC clutch making a clattering sound, air flow problems and a short within the rear AC. On the second visit the dealer found the short in the rear Ac and fried the main AC control. Know I am still having problems with the air flow. I did check the lemon laws here in AZ and filed a complaint with the Better Business Bural I was wondering if you ever resolved your issue and how!
  • thomas40thomas40 Member Posts: 2
    I am having very similar problems with my 2008 Tahoe. I was woundering if you were able to resolve anthing?
  • treedogtreedog Member Posts: 12
    Hey Arrie, I never heard anything back from the post you made on july 21st,I was wondering if your information helped the other two (Natale and Waltherchic) i have the same problem with my chevy tahoe...the a/c works fine but i have the same noise ...its not the tensioner...So I added 1 can of oil,...it didnt help me...i let out a bunch down to 35 and my ambient temp was 90...so 45-55 was my range..Right?..should i go lower then 35?....my a/c still blows cold....it seems a little better since i lowered to 35....but still does it sometimes when i rev the engine at idle...just wondering if i should ad oil from here or let more out first?...Whats your opinion? you have been a great help..I really apreciate your knowledge...thanks
  • natalenatale Member Posts: 5
    Sorry it has been awhile for you to hear back from me i had two deaths in the family since july 21st. I have not tried what Arie suggested yet in regards to the problem i have with my Heat/AC. In a week or two i am going to be putting it in the shop to get it fixed. I have already changed the belt and tensioner and it still makes that noise i described in my first posting. I am willing to bet it is compressor. After i bring it in i will get back to everyone letting you know what they find.
    Regards.
  • waltherchicwaltherchic Member Posts: 2
    We finally gave up. Fall is almost here and we won't need the AC shortly. We snapped 2 tensioners right from Chevy. They put them on, put on the belts, turned on the truck, turned on the AC, hit the gas the tensioner broke. Threw a piece right off. The only thing that anyone can come up with (and 3 guys have all come up with the same thing) is that the Compressor is gone and when we step on the gas, we're putting too much pressure or torque (it's early, and it's been awhile since it was explained to me) and that's snapping the tensioner.

    Basically, we were looking at at least $1500 in repairs to possibly fix the issue on a truck that's worth $5000 and needs new plugs and wires and new tires. $3000 total. I just can't do that right now. So, DH can suffer his 2.5 mile commute w/o AC for a few more weeks.

    Good luck figuring out the issue. I'll check back to see if anyone does find a resolution. The guy who did most of the work for me thinks the tensioner is a piece of crap and Chevy should have made it heavier. FWIW.
  • kiawahkiawah Member Posts: 3,666
    Unplug the compressor power wire. If the driver turns on the defroster in the fall/winter to defrost the windshield, that will turn on the compressor to get the humidity out....and you'll break another tensioner on the road somewhere.
  • treedogtreedog Member Posts: 12
    Natale, Sorry to hear of your losses,..You've had a tough Month. Hopefully i can figure it out for ya ,with Arries help,.. It did get better when i lowered the pressure to 35..Im gonna drive it today and see if the air stays cold and see if the noise comes back.ill let you know...Just waiting for arries advice on wether to lower further before adding oil and freon...Its definately not the tensioner, i put on a new one and it made the same noise right away, so i returned it to the parts store..Thanks
  • arriearrie Member Posts: 312
    Hi there treedog,

    I had not heard back from anybody regarding the issue until today.

    I am visiting in Europe and have not been able to connect to internet. This is the country with Autobahns and it feels kind of good driving 140 MPH in a car that is made for driving fast...but that is another topic.

    If your A/C still blows cold I would let some more refrigerant out. You can do this until you see a drop in the A/C efficiency and then add some back until it works ok again. But before letting more out you might want to make sure you have enough oil in it as oil is lost when you let refrigerant out.

    There is another thing to consider too, which I am thinking to do myself to my own Tahoe...replace the expansion valve.

    Expansion valve can be a problem as it has a very fine mesh screen with it. Over time the compressor wears and all of the metal dust that it spits out is meant to be caught by this screen on the expansion valve. Well, if this screen gets plugged too much it starts to restrict coolant flow thru it and this could be causing some trouble.

    The job includes vacuuming the A/C system before re-charging it.Vacuuming is possible to perform at home too. I have done this in the past a couple of times and it works fine.

    For vacuuming the A/C system you need to purchase another charging hose and then cut off the end that screws to the refrigerant can. Then you find a vacuum connection in your car's intake manifold (there usually are plenty of those) and see what size hose you need to get to connect to one of these ports. Then you get a proper size hose and connect it to the charger hose end that you cut the refrigerator can connector off. Now you have tools to vacuum your A/C system before re-charge.

    You turn off the A/C system (it should not run without refrigeranr anyway but to make sure turn it off) and start car and run it on idle. When idling the engine generates very high vacuum inside the intake manifold. Some cars over 24". When you connect the hand made hose to the A/C system service port and then the other end to the intake manifold port you will vacuum the A/C system very well. You have it "vacuuming" 15 minutes and it is pretty empty.

    After about 15 minutes disconnect the hose from the service port before turning off the engine. Now you are ready to re-charge the A/C system. You will start with a can of oil charge. It will go inthe system without running the engine as the vacuum in the system will pull it in. Then you start with a can of refrigerant and when that stops going in you will need the help of the compressor, i.e. turn on the A/C system for max cooling. This probably will not start the compressor as the coolant level is still so low in the system. To make compressor run you need to short the two wires on the harness that connects to the pressure sensor that is mounted on the side of the dryer bottle.

    A new expansion valve is very low cost item. Last one I bought for my Dodge Ram tryck cost $6 or something like that. Expansion valve is located inside the tubing where there is a union on the line just before that dryer bottle. If you run the A/C before the job you can feel the line for temperature as before the expansion valve it is hot and after the valve it is cold.

    Arrie
  • treedogtreedog Member Posts: 12
    Hey Arrie , Glad your having fun...I have a European friend that would love to bring his BMW back from Florida and drive it on the Autobahn...

    O.k im at 35# refrigerant now, so should i drop it to 25 and add a can of oil and then some refrigerant if it needs it?..Or just put in some oil now at 35?..(My oil cans say they have 2 ounces of oil and 2 ounces of refrigerant)..Id like to try one of these options first before i vacuum the system .Right?.

    It should have plenty of oil because before i drained it i added a can to see if it would help...then after it didnt help, i added another can..and it still didnt help...And then it was in the danger zone .(above 60)..so i had to let it out anyway...so i backed it down to 35..

    Then what about the oil and freon going into the vacuum line of the intake.That wont hurt anything?.What about a regular shop vac adapted to fit the hose from the end i cut off?

    If the air is ice cold at 35 with a ambient temp of 90 ..Then would you still think the expansion valve is restricted?..Seems like it would be noticably warmer if it was restricted since at 90 degrees it recomends 45-55.

    I was told to use the 150 vicosity oil..And that the 100 was ford and 46 was dodge..Am i using the correct oil?..Thats what they said at Autozone anyhow..

    Thanks for all your time. I really apreciate it
  • arriearrie Member Posts: 312
    If you added two cans of oil at first then I think you can let some more refrigerant out and like I said you will see when you are too low as your cooling will start suffer.

    As your compressor already is years old meaning it is not the tightest one I would use higher viscosity oil. It's like with old car engines. High mileage engines benefit from higher viscosity oil as fit between piston and cylinder is not that tight any more.

    And make sure you run also the rear seat A/C as it works from the same compressor when you evaluate if it still blows cold or not..

    Vacuuming the A/C system using a intake manifold port should not harm anything in the engine. I think the only component that could get harmed from the A/C system oil is the MAF sensor, but this sensor is mounted right after air box in the ambient pressure environment. The only sensors that are in the engine system that would see the A/C oil are the O2 sensors but they see engine oil anyway so I don't think A/C oil would hurt them especially because very little of it will be coming out from the system when you vacuum it.

    Shop vac will not provide any real vacuum that would be sufficient for A/C system vacuuming. You either need to use a specially made A/C vacuum, like people working on home systems use (or car systems) or use the car engine vacuum. I have done this on a Lincoln that I had many times when I had problems with seal leaks and also with my Dodge RAM truck when I changed the expansion valve and dryer in its system.

    Have you noticed any difference in fuel mileage after you dropped the A/C system pressure?

    Why I mentioned the expansion valve as a possible problem is that it can cause it two ways. Either the screen of it can get plugged or the orifice wears out to too big opening.

    If it gets plugged it can cause over pressure on the compressor output side and if the compressor is equipped with an over pressure port it can make noise when this port open up and re-circulates refrigerant back to intake side of the compressor. In my Dodge the over pressure valve spits the refrigerant out, which was a clear indication of my expansion valve being plugged, like it was when I finally changed it.

    If expansion valve wears to too big opening it can let too much liquid refrigerant thru it on the intake side of the compressor, which is not good. Liquid does not compress so it can cause over pressure in the compressor and be the cause for the noise.

    Arrie
  • jl222jl222 Member Posts: 1
    i have an 05 tahoe with the same problem, blowing from the defrost. I was going to buy a new replace the controller but wanted to see if you resolved your issue another way? Winter is coming and my heat does not work either! :(
  • ahightowerahightower Member Posts: 539
    A little late to this dicsussion, hope someone is still watching. I started to get the buzzy sound from the aspirator. Quite annoying. I pried off the cover and blew out all the dust and sprayed in some WD-40. I don't think it did any good. I guess it's time to replace it. I'll let you all know if I succeed in that. I was able to access it by partially removing the weather stripping and the A-pillar trim piece, but I could barely get the plastic cover back on, there was not much "give" in the headliner and it was very difficult to reach the aspirator just to hold it still and get the plastic clips back in for the little cover/grille thing. Perhaps if I unscrew the thing holding on the sun visor that will provide more room to work. I would like to try it myself. If I can't do it, then I'll take it to the dealer and let them use the part I already bought. Anyone else done a DIY on this thing yet? Or, better yet, do I really need to replace this thing? Why is it buzzing anyway, does it need a good cleaning or is the little electric motor dying on me?
  • bingrambingram Member Posts: 1
    I have an 02 Surburan with an air flow control problem. When I turn the control knob to change the air flow direction ( ie from heat to defrost ) it does not change direction. The only place air blows is out of the dash outlets. Does anyone know what the fix would be?
    bingram
  • tmjmredtmjmred Member Posts: 1
    I might have a solution for some of you that had the climate control fail to defrost mode only, after I replaced the battery. I tried several things that I read about on different forums and while I was playing under my dash I bumped my Power Seat switch. To reset the seat position, I pushed my Driver preference button and my Climate Control defaulted to my old setting and is now working.

    04 Tahoe
  • ahightowerahightower Member Posts: 539
    Regarding the buzzing aspirator, I've come across the following in a couple other forums:

    Document ID# 1639237

    Subject: Buzz Noise From Headliner Above Driver - keywords ac air aspirator cover fan grille HVAC interior microphone sensor speaker temperature vent vibration
    #PIT3511 - (03/29/2005)

    Models: 2000-05 Cadillac Escalade

    2002-05 Chevrolet Avalanche

    2000-05 Chevrolet Silverado, Suburban, Tahoe

    2000-05 GMC Sierra, Yukon, Yukon XL, Yukon Denali

    The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.

    Condition/Concern:
    Dealer or customer may comment that they have a buzz or vibration noise emanating from the headliner in an area that looks like microphone or a speaker.

    Recommendation/Instructions:
    The plastic escutcheon grill, which is round and about the size of a half dollar and located just above the driver to the left, is the interior ambient temperature sensor. The sensor is used in conjunction with the automatic HVAC (C68). On occasions, this sensor has been known to make a buzz or rattle sound. The sensor uses a small fan to pull air over the sensor. This buzz noise may be intermittent.

    Although it may not be possible to alleviate all of the buzz or noise from this sensor, Engineering has found that if the sensor is installed incorrectly that it may bind and cause the fan to make a buzz noise. Remove the sensor and while doing so check for any binding. Reinstall the sensor and re-test. If the noise is still present, the sensor itself may be noisy and require replacement.


    ===
    My question is, is this document a TSB or a recall? Does this mean that a dealer would address it free of charge despite being out of warranty? Mine is a 2005 Yukon XL. I can't seem to find this on any official GM site, and I'd like to have something to back me up when I go to the dealer. From what I've gathered, they will charge about $60 for the part plus an hour of labor. I'm having no luck finding this one GM's own website. Thanks for any help.
  • ahightowerahightower Member Posts: 539
    I bought the part from my GMC dealer for $44 + tax and installed it myself in 10 minutes. Just remove the visor (left side only, and you'll need a torx driver, not philips), gently loosen the A- and B-pillar trim, pull back the weatherstripping, and you're in. Pop the grille off with a flat screwdriver, have your lovely assistant gently pull down on the headliner so you have room to work, and then simply unplug the old aspirator and plug in the new one. Snapping the little grille back on was a little tricky. But it's done and it's silent and as far as I know it works. We'll be going to Marble Falls, Amarillo, and Houston over the coming holidays, and I would have gone insane listening to that for 1500 miles! Also glad I didn't wait around the service shop and pay for an hour of labor.
  • krd120203krd120203 Member Posts: 4
    I have an 2003 and my blower is only working on setting 4 and 5. It is blowing at what it would for these two settings. At 0 to 3, the air is just lightly flowing though the vents. What could the problem be?
  • krd120203krd120203 Member Posts: 4
    My climate control is only working on the settings of 4 and 5. from 0 to 3 the air comes through as a breeze. What could be the problem with my system? The blower is working at the correct strength at both 4 and 5, and the rear blower is working just fine in all settings.
  • arriearrie Member Posts: 312
    I had the same problem with a '02 Pontiac Grand Am and it was caused by burned out blower speed control resistor.

    In that Pontiac blower fan speed control is done with resistors, i.e. with each fan speed the voltage to the fan motor goes thru a different resistor, which drops the voltage for the motor for a set fan speed. Resistors are located in the air flow duct by the fan, i.e. the resistors that heat up as they lower the voltage are cooled by the air flow that the fan makes. This is why it is the lower speed resistors that usually fail because the air flow is lower. I also think there are more than one speed connected in series so when just one of those burns it takes all of the speeds out that are in that series. I also lost lower 3 fan speeds when it happened.

    As I said above this writing is with a Pontiac Grand Am but I would not be surprised if your Tahoe would have exactly the same construction for blower fan speed control so look at the air duct around the blower. You might find a small circuit board bolted in the side of it, which has those fan speed resistors built into it. You can probably buy a new one at car part store other than a dealer just as I was able to for My Pontiac.

    Arrie
  • beckya1beckya1 Member Posts: 1
    Hi - I need to know if I should add Freon (or the alternative) to my A/C system on my 1999 Tahoe. The past 2 seasons the A/C has become progressively 'less' cool. I turned it on the other day when it was only about 65 degrees out and it didn't cool at all. It wasn't blowing hot air - it was just blowing.

    So - should I add coolant to the A/C system and if so - what and how?

    Thanks!
  • ackingacking Member Posts: 6
    With the engine off, turn your compressor clutch by hand and make sure that you don't have any tight spots. The problem could exist from a compressor that might be ready to sieze. Also have the air conditioning tested to ensure that the charge levels are good, overcharging a system could lead you on a wild goose chase of strange noises.
  • ackingacking Member Posts: 6
    Only use virgin R-134a refrigerant. Drop in refrigerants aren't such as dura-cool aren't really safe for A/C systems. Always refer to manufactures spec!
  • arriearrie Member Posts: 312
    What age is your car?

    Well, regardless of the age you might have lack of oil lubricant in your A/C compressor,

    If the belt "flaps" it probably does it at frequency of pistons moving in the compressor. This would mean that your compressor causes more than normal torque peaks as it turns around.

    Unless you have severely over filled you A/C system the first thing I would do is to get a small bottle of A/C lubricant and fill it in and see if it helps.

    If you are a little bit hands-ON person go get a A/C kit with refrigerant, oil fill and pressure gauge. These are not expensive and can be found in any car parts store.

    First measure pressure by the instructions with the gauge, i.e. run engine with A/C ON for a few minutes and connect gauge on the low side service port (it should not even fit on high side where you NEVER want to connect). Low side service port is in part of the line that gets cold.

    If pressure is not too high add oil lubricant again in the low side service port and see if it helps.

    If the pressure is too low add refrigerant but you say it works fine, i.e. refrigerant fill should be good and low fill should not cause too high torque on the compressor anyway.

    Over filling the system can cause this issue, i.e. you would have A/C refrigerant entering the compressor in liquid form, which does not compress and would cause very high torque pulse. This can cause severe damage to compressor too.

    Arrie
  • zigfreedzigfreed Member Posts: 1
    Did you ever figure out the Air flow problem on your suburban, I am having the same issue.

    Thanks
  • krd120203krd120203 Member Posts: 4
    I did find out what it was. It is a fan blower resistor. It is located under the glove box. It is extremely easy to fix. I was only able to find the part from GM. Napa did not have it and could not get it for my model year. It took me maybe 10 minutes to take the cover off and switch the part out.
    Hope this helps you.
  • suburban68suburban68 Member Posts: 3
    Hi all.
    I own a 2000 C1500 Suburban.
    HVAC equipment is C60 (front, manual control) and C69 (rear, manual control)
    As I can find easily used controls on eBay, is there any way to simply upgrade my AC to electronic control? Is wiring pin to pin compatible?
    Olivier (from France) :D
  • carlosrubio310carlosrubio310 Member Posts: 1
    I had the same problem. I replaced the ac compressor ( rebuilt) and work good its been about 1 year ago, i did the repairs my self, I spend about $200.00
  • sulli031sulli031 Member Posts: 1
    I have a 2002 Tahoe and the fan works on blower settings 1 - 4 but shuts down on setting 5. Any ideas what's wrong and how to fix? Thanx.
  • blackpacific1blackpacific1 Member Posts: 27
    My 1999 Suburban blows warm AC in the front, and ice cold air in the rear. It also does not have the lower fan speeds, most of the time they are not working, but intermittently they will work, while the high speed position works most of the time. I think this problem might be a bad fan control resistor, but I am not sure how it would impact the front AC operation. Any suggestions?
  • noclue1970noclue1970 Member Posts: 1
    I have the same problem on my 1999 tahoe did you find the problem?
  • bamahoovbamahoov Member Posts: 1
    I have a 04 Tahoe, and its doing the same thing with the AC. The front vents blow hot ait, but the back vents blow out cold air. What the deal? Thanks guys.
  • blackpacific1blackpacific1 Member Posts: 27
    Problem fixed. I went down to Walmart, bought a 22oz can of R134 freon with oil and sealant in it. I turned on the Suburban, put the AC in max high, heard the AC clutch engage, disengage, engage, disengage, a sure sign that the freon is low. I had two ports to choose from, only one is small enough for the coupler to snap over. I blew some freon through the hose as I connected it to push any air in the hose out. I squirted freon into the system until the AC compressor quit clicking on and off. Then I continued to squirt until the pressure was in the low range on the gage for the given outside air temperature. The instructions for this are right on the can, it is a no brainer to do this! I used almost the whole can. Towards the end of the recharge the cheap hose connection started to leak, so I disconnected. But it was a good enough recharge that the Suburban has cold air in front and in the rear. I still have a bad fan switch problem that remains unsolved. I think we have low and high, but nothing in between.
  • j_nolesfanj_nolesfan Member Posts: 1
    I have an 02 Tahoe LS 2WD. Something weird has been happening lately. I've searched through a lot of the posts in this thread and haven't seen this issue exactly.

    I usually run the front AC on the mix setting where it's blowing through the dash vents (not the defrost vents) and the under dash vents with the air set to recirculate. When using this setting, and the fan is at 2 or higher, all front dash vents work normally. If I switch the fan to 1, the vent in the center of the dash (by the radio) stops blowing air. This just started. I know there are actuators under the dash but why would one change it's configuration just because I changed the fan speed? The only other explanation I can imagine is that he actuator won't move fully into the proper position and the fact that the air speed is lower on 1, it doesn't generate enough air pressure to pass the actuator. Any advice would be much appreciated.

    Thanks in advance,
    Jeff
  • z7onez7one Member Posts: 1
    i have read some post on this site with people having the same problem but i have not found the answer yet. the front climate control is working just fine with the heat , ac , defrost, ect... the problem is that nothing at all is working for the rear climate control. if anyone has the answer that would be great or even just a starting point.
    i have checked all of the fuses hoping that it might be that but they all seem to be just fine. thanks for the help,.
  • frankd28frankd28 Member Posts: 1
    This thread saved me some time and money so I thought I post my experiences in case it may help someone else.

    Vehicle: 2002 Chevy Tahoe with climate control
    Problem: AC ran full blast constantly (when set to auto)

    Replacing the aspirator as described in this thread fixed the problem.

    I bought the part( pn: 25903301 ) online from GM Parts Direct for $24, shipping and handling was another $13. I did find the part online at another vendor for the same price but $5 bucks less in shipping. But I placed the order with GM Parts Direct since they had done the legwork regarding the part number. They were prompt and efficient; delivery took 5 days.

    Installation took me about 30 minutes after doing some reading on how to "loosen" the b-pillar. It turns out you just give it a tug straight out. It snaps on and off. Finding some online notes on how to replace the headliner gave me the confidence to just pull on it. It was tight quarters to get at the aspirator to replace it but doable.

    The boss tells me her AC works great now so I'm very pleased with how this repair went.

    Frank

    P.S. Our Tahoe has been very good to us and we hope to get several more good years from it. It has 97,000 miles on it and the only significant repairs have been a new fuel pump and some substantial rear brake work. (knock on wood)
  • mrwizard88mrwizard88 Member Posts: 2
    Anybody remember how much PAG 150 oil to put in the compressor when you change out the AC parts. Thanks in advance for the help
  • mrwizard88mrwizard88 Member Posts: 2
    By the way the vehicle is a 1994 chevy suburban with rear AC, thanks.
  • e7boatse7boats Member Posts: 1
    Dash A/C Blows cold. Rear Blower works, air flow is correct, and rear evap is cool but not cold. Anybody got any ideas what the problem could be?
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