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Chevrolet Blazer Heating and Air Conditioning

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Comments

  • jlflemmonsjlflemmons Member Posts: 2,242
    Check the vacuum lines running from the intake manifold over to a tee near the brake vacuum booster and on to the vacuum resevoir in the left front fender. Very common for these to rot and leak with age, and will cause the symptoms you have described.

    Good luck
  • gunnysargegunnysarge Member Posts: 1
    Guys my WIFE'S 2002 blazer has no heat .. i pulled the return heater hose and NOTHING.. one side is hot and the other nothing( its a little wet but no running water)... ???? can I use a air line to maybe blow the core out??? or is it to late and i have to replace it......????
  • jlflemmonsjlflemmons Member Posts: 2,242
    Backwash it using a garden hose, just don't crank the pressure up too high. Get garden hose repair fittings and install them on heater hoses a couple of feet long. One will be larger than the other. Hook the supply side hose to the "exit" tube on the core, and the drain side to the other. I *think* the smaller one is the supply side, but not sure.

    Gently turn on the water and watch for crud to come through the drain side. Once it starts flowing freely, let it run until the water coming through is clear.

    Put everything back together and get the system flushed and refilled with fresh Dexcool. Do not try to switch to standard antifreez unless the whole cooling system is flushed until the drain water is drinkable! (just kidding, but it needs to be completely flushed) Those two types of antifreeze will not play together, and even a little bit will cause problems.

    With a little luck, the corrosion will not have eaten through the heater core.
  • bigdaddy6886bigdaddy6886 Member Posts: 1
    Issue: no heat. A/C works fine, blower works fine, but it seems when I turn the temp control knob, it turns too easily. I understand there is a baffle that the knob controls to reroute from A/C to heat, but not sure where it is or how to get to it. My thermostat is fine, but going to replace it anyway, along with a new radiator cap. Have not completed a coolant flush, am scheduling that in the next couple of weeks. I also heard it might be some sort of relay switch, located under the hood near the firewall? Any assistance?
  • dfhltddfhltd Member Posts: 11
    The first thing you should do is go to the dealer and get them to copy the diagrams from the parts catelog. There are acouple of them that show different views. Also get the pages which list the parts and description that go with the diagrams.
    this will help you find the baffels or doors (3) that control airflow and the parts that control them. Check the hoses at the firewall going in and out of the heater to see if they are hot.
  • stealthnystealthny Member Posts: 25
    Hello I have a 1997 Blazer. The heat didnt work when I got it. I direct wired the blower to the batt and the motor was fine. I replaced the switch that operates the fan speed and it worked for a week. Now it only works sometimes. If I hook a direct connection to the fan fan it always goes on. Also I noticed that the heater doors dont appear to be working I can only get defrost and some heat out of the bottom. are these electric or vaccum? I live in upstate NY ( 14 degrees here today )so I really need the heat and defrost any suggestions?

    Thank You
  • stealthnystealthny Member Posts: 25
    Hello I have a 1997 blazer. I took it to get it inspected but because I installed a new battery and only drove 40 Miles it mech. said it wouldnt read it yet. I have since put on 140 miles and 2 days ago the check engine went on and stayed on for the afternoon. The next day it was off and hasent been on since. I brought it back for th einspection and again it read " computer not ready to read) Can anyone tell me why or what I can do. I need an inspection. Please note I took it to a friend of mine who has one of these hand held computer checks and he said it didint show any errors that I should be fine. This was BEFORE my return to the shop for inspection.
  • rlhirstrlhirst Member Posts: 1
    I have plenty of heat. The problem is it only blows out of the vents no matter what position the switch is in. I replaced the control panel but the problem remains.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Check the vacuum lines from the intake manifold, to the tee near the brake booster, to the vacuum resevoir in the drivers fender behind the underhood fuse box. These lines rot and since the controls are vacuum operated, they won't work.

    Jim
  • yourangelladyyourangellady Member Posts: 1
    My girlfriend owns a 1998 Chevrolet Blazer....She was told recently by a mechanic that if you don't use your A/C much, it could actually harm your engine. Is this true at all ?

    I would appreciate some help on this. Thanks so much.
  • tidestertidester Member Posts: 10,059
    I've never heard that before and don't know how it's possible but maybe someone else can offer some insight.

    tidester, host
    SUVs and Smart Shopper
  • dfhltddfhltd Member Posts: 11
    Whoever told your girlfriend that is nuts. AC takes power from the engine just like the alternator, the power steering and the transmission and wheels. The AC is no different. That's what the engine is there for. Engines in cars made without AC do just fine. There is no way that not taking energy from the engine is going to hurt it.
  • steverstever Guest Posts: 52,454
    In the old days, you were supposed to run the AC a few minutes a month all year round. As I recall, this was to keep the seals flexible (in the compressor I guess).

    Nowadays the AC will kick on when you run the defroster to dehumidify the air, so you shouldn't find anything in your manual about running the AC. And I don't see why never running the AC would hurt anything.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Has nothing to do with harming the engine. But you should run the ac or defroster at least once a month for a minute or so to keep the seals lubricated and the oil moving across the moving parts of the compressor.
  • dulinaadulinaa Member Posts: 10
    Try looking straight down the firewall from where the a/c lines enter it. Do you have any condensation on the ground at all? Is the front floor carpet wet? There isn't much room for any kind of sloshing around. I have had heater cores with trapped air make that sound, especially the chevy trucks. And on my in-laws Jeep Cherokee, that drain was plugged bad, but it was inside the square tube subframe that extends from the firewall, couldn't get to it to blow shop air up to clear it.
  • dulinaadulinaa Member Posts: 10
    It will not harm your engine, BUT it can ruin you a/c by not running often. Its got the Use it or lose it policy. Your a/c system has lubrication oil mixed with and circulated by the refrigerant. The seals can dry up and crack, especially the front shaft seal on the a/c compressor, causing all the refrigerant to leak out.
  • steverstever Guest Posts: 52,454
    I just downloaded a '98 Blazer owner's manual and I don't see anything in there from GM advising owners to run their AC at any time. It may have been an issue in the old days but I don't think it must be a problem now; otherwise the manual would say something.

    How To Find Your Car Owner's Manual Online
  • jlflemmonsjlflemmons Member Posts: 2,242
    Steve,
    Running the compressor is an issue in any automotive system. It may not be mentioned as most folks will use there defroster/defogger during the winter, and thus run the compressor.

    It may not be as big an issue with R134A, but was definitely an R12 issue. Most systems now days use very, very little refrigerant. As an example, the S10 series Blazer/pickup uses less than 28oz of R134A!
  • steverstever Guest Posts: 52,454
    edited June 2010
    I think the long term trend in cars is to lessen required maintenance as much as possible. So my feeling is that the engineers have improved the seals so that there is little risk of failure by not using the AC. Plus as you say, the AC comes on with the defrost.

    Then again, I suppose the manufacturers know that most people trade cars every 3 to 5 years and so they don't mention maintenance for marketing reasons, since many (most?) of us don't want to maintain things. But both my cars are over 10 years old and I just use the AC or defrost as needed, not on some "monthly" schedule.
  • ncastorncastor Member Posts: 4
    I own an 04 Blazer LT with 4WD and the heat was blowing cold. The mechanic received a code indicating the thermostat needed to be replaced. They also replaced and winterized the antifreeze, etc. That was on Thursday. On Sunday it was again blowing cold.

    I felt it was a partially clogged heater core but they replaced the thermostat which seemed to resolve the issue for about 2-3 days.

    Any suggestions and should the dealer do the repair free of charge for not fixing it initially?
  • dfhltddfhltd Member Posts: 11
    To tell if the thermostat is bad, look at the temp gage on the dash. It shoulkd be in the middle. If it's way in the cold zone it's no good. Assuming the coolant in the engine is hot according to the gage then the heater should be getting hot coolant. Find the two hoses that connect the heater to the engine and wrap your hand around them to see if hot coolant is flowing in them or not. If they are hot you have a problem with the air doors inside the heater and the control that adjusts how much hot and cold air to mix. Yours could be stuck sending all outside cold air and no warm air. I don't know about your model but some have a water control valve that controls the volume of hot water the heater gets. It might be stuck shut. find it and test it to see if it opens and closes when you apply 12v to the terminals. If it works it is still possible the signal from the heater controls is bad and telling it to shut off. Then you would have to find out why there is no signal when you turn the controlls to max heat.

    Good Luck
  • bear95bear95 Member Posts: 1
    #28 of 135 Too much heat! by focker1993
    Jul 21, 2007 (12:50 pm)
    I have a 1999 Chevy Blazer with the climate control. The problem is with my heat, it never stops. It constantly blows heat out of the vents. I can still change the direction ( defrost, floor, vents) and the speed of the blower, but cannot shut it off. The AC will not come on, the light comes on, but never any cold air, which I am thinking that it has something to do with this. I am looking for any suggestions please. It is hot outside and is unbearable sometimes to drive. Thank you very much

    Any help to share a solution to this posting? Thank you so much
  • pokey164pokey164 Member Posts: 1
    I have a 98 blazer and have no a/c dont know where to start
  • hewybohewybo Member Posts: 10
    my 95 blazer overheated today -got it home -filled with water -fine, no leaks. turned on a/c compressor,; within 2-3 minutes, sprang a leak. cannot find source, but it's dripping down on right side of bell housing area ( i think). the a/c condenser and heater core are separate, right? why a WATER leak when running a/c?????
  • alex85061alex85061 Member Posts: 5
    What are the best replacement wiper blades for our vehicle?
  • duntovduntov Member Posts: 133
    Original equipment
    AC Delco 8-2162 (GM-89000993)
    16"insert with steel frame.
    front
    RH and LH wiper.

    The have the AC Delco logo faintly printed on each blade to keep your Chevy all GM.
  • bigboy66bigboy66 Member Posts: 3
    This problem is caused by an Electrically Operated Temp/Blend door that is controlled by the Tempature dial on LT models with "Auto Climate Control". (If yours has a temp control dial with numbers from 65 to 85) Anyway this door is controlled by an electric motor that opens and closes the door to vary the temperature. This motor Is called the Heater & A/C Blend Door Actuator. Its Part Number is (Dorman 604-106) This motor can be replaced by dropping down the Glove Box, and reaching through. Its right on top of the heater box. The motor is expensive - around $100 - $120. That should fix your problem.
    Scott - ASE Master Mechanic
  • hotrodgaskethotrodgasket Member Posts: 1
    I have a 2000 Blazer. The fan may or may not run. When it does run, the air temp is ok and heats the vehical and /or defrost the windsheild just fine. The controls check out ok. I think it is the vacuum system but I have no idea where to start, Any ideas?

    Thanks,

    John
  • rr_illinoisrr_illinois Member Posts: 2
    John,

    I am working through some issues with my '99 Blazer. One thing I do know is the fan won't come on at all until there is hot water (anti-freeze) coming through the heater core. This is a built in function to prevent the system from pumping cold air into the cabin. You say that when it does turn on it works just fine. Perhaps that is the situation you are experiencing. Start your truck and let the engine come up to heat and see if your fan turns on.

    Rick
  • rr_illinoisrr_illinois Member Posts: 2
    I have the exact same issue with my '99 Blazer. I'm glad to hear there is someone else having this issue. Maybe now we can work on it together to resolve.
    If you have resolved since you posted perhaps you would be willing to share your experience with the rest of us.
    Thanks.
  • janderson91janderson91 Member Posts: 1
    I have a 98 Blazer with Automatic Climate Control, It had started out as a problem of no heat. Then we replaced the Control Module and that gave a little bit of heat being blown, only issue was the blower motor wouldn't turn off until you pulled the fuse.

    That lasted for maybe 20 minutes and then blower motor stopped again, this lead to us replacing the blower motor. With this it still will not turn off even with the engine off.

    The speed control knob on the dash isn't functioning the way it should, you can turn it all the way to off and still would be blowing full speed.

    So I don't know if this would be the issue and would resolve these problems. Just trying to look for some solutions as its pretty cold here and having to pop the hood to take out fuse all the time is less than ideal.

    Any help would be greatly appreciated, Thanks!
  • geno69geno69 Member Posts: 1
    My actuators look to be all working, just no air comes out on the floor. when you select the floor the air comes out defrost area.
  • jlflemmonsjlflemmons Member Posts: 2,242
    edited February 2012
    Oh, I have seen this one before, several times. The vacuum line that runs from the intake manifold to the vacuum resevoir in the drivers side front fender is rotted/leaking. It runs from the drivers side (left bank) of the intake manifold on the engine to a "tee" near the power brake vacuum booster. Check all the hoses and replace them if rotten. Actually, just replace them all because if some are bad, all will be close to bad.

    In the case of a vacuum loss, the directional damper will not move correctly.

    Will cost about $3 in vacuum line and takes about 15 minutes.
  • bdean8183bdean8183 Member Posts: 1
    edited February 2012
    I have a 99 Blazer with the auto climate control. About a month ago the blower motor would come on sometimes and sometimes it wouldn't. Seems like in the morning when it was cold it wouldn't come on but in the evening when it was warm it would. When it would come on everything would work great. It finally got to where it wouldn't come on at all so I wired it to the battery and ran a switch in the cab so I could just turn it on and off so I wouldn't freeze. When I flip the switch for the blower it blows strong but no matter what I turn the temperature to it blows hot air and cold air. What I mean is, it will blow extremely hot air for about 5 seconds then it will blow cold air for about 5 seconds. I can hear something in the dash making a clicking and whining noise now. I didn't notice this until I wired the blower to the battery. Before I wired the blower straight to the battery, I measured the voltage at the plug that plugs into the module. I've got 12 volts between the orange and black wire and 12 volts between the black/white and black wire. I also measured the purple and black wires that come out of the module and go into the blower motor. I've only got .0443 volts at those wires. I got another module out of a junk yard and it gives the same measurements so I don't know if I've got two bad modules or this just isn't my problem. Any help would be greatly appreciated because I am stumped.
  • deftinwulfdeftinwulf Member Posts: 1
    I have a 1998 Chevy Blazer ST-10. Recently, the fan decided it was only going to come on sometimes. It will come on when it's freezing cold outside. I've pulled fuses reset the computer by disconnecting the battery. The heat is on, but the fan will not kick on. It doesn't matter if it's on A/C, defrost, or heat. As well, when it does decide to come on, it will not blow on the floor. We're in the middle of a winter storm right now in Northern Michigan, and I'd really like to have my heat back without paying an arm and a leg.
  • jdaniels2jdaniels2 Member Posts: 1
    hi ive been working on tis right now found out there is a line that goes into the fender..see if that has fallen off..its very small and u need a mirror to see it,when that's off it defaults to defrost and vents only.
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