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Chevy Silverado and GMC Sierra Climate Control

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Comments

  • You sound like you know what your talking about. My '05 Z-71 is doing the same thing, are you sure it is a diode in the switch? If so, is it easy to get to? I can fix it if it's easy to get to, sometimes they hide those things, just to see how tenacious, or stupid, you are. 79 cents and an hour and a half sounds better than $200 to $300. By the way, my wifes '03 suburban had the same problem, electronic control, $6oo to repair it! ebay replacement $125. 1hour of time.
    thanks for the help!!
  • obyoneobyone Posts: 8,054
    From what I've read in the forums its a no brainer since you already know how to remove the control unit. I believe there are a couple of screws on the backside which allow you access to where the diodes are located and a simple solder job to do it.
  • thanks, I'll try it this weekend if I have time and let you know how long it takes.
  • wynnsomwynnsom Posts: 2
    I have a 2001 Chevy Silverado A/C problem. The compressor cycles on and off very fast. It does blow cold but not long enough to cool the cab, inside temp is 120 a/c cools down to 80. System appears to be full. Can you Help?
  • obyoneobyone Posts: 8,054
    "The compressor cycles on and off very fast."

    Do you mean it cycles frequently? That usually means its low on R-134a.
  • wynnsomwynnsom Posts: 2
    The compressor cycles on then you can count to 15 then it cycles off and then on and then off all the time the ac is on.
  • snmfeesnmfee Posts: 2
    Are there vareations to the ACM on modles? My AC quit after I fixed the High on fan relay. Burned up wire connector. If ACM goes out will it stop dampers from changing and not trun on AC relay under hood?
  • jdebordjdebord Posts: 1
    So this just happened to me I believe in my 2005 Silverado. I was driving down the interstate, and when I pulled off the truck started blowing really hot air and the controls still said the A/C was on.

    Fired it back in this morning and the A/C was working...any solution? I'll post back if I find anything.
  • No joy, switched the control unit, same problem. Next step is to check the blower resistor module. Did some more research and this is a common problem. Part is cheap, $35.00 on line, GM even manufactured an upgraded version in early '06. After I go through all of this I'll get back to you, won't be til after labor day.
  • grampy1grampy1 Posts: 140
    2004 GMC Manual says truck may,or may not have a cabin air filter. Kind of a dumb statement,but i'm wondering if it has one where it is. Truck has AC
    Thanks :confuse:
  • obyoneobyone Posts: 8,054
    It's located under/behind the glovebox. Whether there is a pair or not there is a slot there for the filters. At one time GM sold this as an option back in 2000. You can find detailed instructions buy doing a search on the GMC Sierra/Silverado topic on how to change, the part no., and why you should have it.
  • grampy1grampy1 Posts: 140
    Thanks
  • obyoneobyone Posts: 8,054
    you do need to drop that a/c evaporator cover which is made of something resembling insulated cardboard. It is held there with 3 8mm bolts.
  • grampy1grampy1 Posts: 140
    I'll check that out to. Thanks again.
  • grampy1grampy1 Posts: 140
    I have come to the conclusion that my Truck doesn't have one.
    I re-read the owners manual and could NOT find any reference to a cabin air filter in the section that lists items that need servicing such as air filters,oil filters,type of brake fluid,etc. No mention of a cabin air filter. Thanks for everyone's input. ;)
  • obyoneobyone Posts: 8,054
    Even though you don't have the filters installed now I believe you can install them. Same thing with my '00 Maxima. It didn't come with the filters installed and when I checked there was the compartment just no filters. So I ordered some and installed. Keeps your air clean and your evaporator core. Might want to take the time to check.
  • Obyone,
    Wasn't the controller, turned out to be the blower motor resistor/relay under the passenger side dash. Got it from rock auto, about $30 less than dealer, took about 10 minutes to install. All is well with this fix. Bought a new cabin air filter at the same time, instructions with the filter and the Haynes manual are not up to date for the '05's any idea on where and how to change this on an '05?
  • obyoneobyone Posts: 8,054
    From what I understand the cabin air filters were discontinued from '03.

    http://www.gm-trucks.com/forums/index.php?showtopic=66405&hl=cabin+air+filter
  • Its not the control module or the blower resitor. Its Open pin 1(Big red wire) on the connector. This connection gets hot and melts the connector body causing an open connection
  • Absolutely correct per Chevrolet Dealer Service
  • No, I replaced the resistor/relay module and it works just fine. There was some obvious heat deformity to the red wire you describe, however not enogh to cause a problem. We've been in the high 80's low 90's since I did the repair and have used the high setting several times with no problem. Time of course will tell, but so far no problem.
    dm
  • I have a 2003 Siverado 1500 that has recently developed a problem with the recirculation door. The door continues to flap when it moves into the non recirculation position(towards you when looking in from the lowered glove box). It flaps a couple of times when put into the recirculation position(away from you when looking in from the lowered glove box) but then stops. As long as the recirculation is selected the door remains in position. When recirculation is turned off, the door comes forward and continues to flap. I am pretty sure I probably have to replace this motor, but have no idea where to begin. Any guidance would be greatly appreciated. I have a Haynes manual, but it only refers to this motor, it doesn't list any removal/replacement procedures. Thank you in advance for any help you can provide. Mike
  • My silverado leaked on floor under dash on passenger side. The ac was run for 4 hours before i noticed. it looks like the duct under the paseenger side was sweating then dripping down. Not a lot but several good size drops. Is this normal?
  • Mike, I"m having the same problem as you - I think! there's a weird noise coming from under the dash on the passenger side. It's intermittent and of a mechanical nature . I looked under there but it's all concealed. The noise happens whether the fan is blowing or not and I can feel there's something going on with the recirc. fan and the flap. Mine is a '98 gmc sierre 4wd. have you had any luck finding out what the problem is? I obviously want to take care of it before something really drastic and expensive happens.any help will be appreciated, Andy
  • Andy,
    I have not had any luck in fixing this problem. I really thought that someone on this forum would have had a suggestion or a tech bulletin to help, but no.
    I'm hesitant about trying to work my way into the dashboard to try and find the problem. It's not like the old days when the dash came off with just a few screws and clips. A lot of electrical connections and of course the airbag.
    Right now I just keep the recirculation turned on and it doesn't flap. Which is O.K. now that its getting cool, but will definitely need to fix it before next summer.
    Good luck with your situation. Mike
  • I've been reading the posts about the climate control issues. Here's my problem: It's that time of the year. I use the heat in the morning, and want AC when I come home in the afternoon. If I don't change the controls over to AC before I get out of the truck, I'm still going to have heat later in the day when I get in to drive home. If I forget, and start the truck with the controls still in the heat position and try to change to AC on the way home, I'm going to get hot air even with the AC on.

    Here's another problem: On a long trip, cold air comes in on the passenger side, under the dash, from the upper right. It's like there's a vent open, but there's no way to close it. Turning all the climate controls off doesn't solve the problem. The only solution is to cram a jacket or blanket in the spot where the cold air is coming from.

    And then there are the times on a trip when it gets too cold or too hot, and there's nothing I can do but pull off the road, shut off the truck and have lunch. After it sits for a while, the controls sometimes work the way they're supposed to.
  • I've been reading the posts about the climate control issues. Here's my problem: It's that time of the year. I use the heat in the morning, and want AC when I come home in the afternoon. If I don't change the controls over to AC before I get out of the truck, I'm still going to have heat later in the day when I get in to drive home. If I forget, and start the truck with the controls still in the heat position and try to change to AC on the way home, I'm going to get hot air even with the AC on.

    Here's another problem: On a long trip, cold air comes in on the passenger side, under the dash, from the upper right. It's like there's a vent open, but there's no way to close it. Turning all the climate controls off doesn't solve the problem. The only solution is to cram a jacket or blanket in the spot where the cold air is coming from.

    And then there are the times on a trip when it gets too cold or too hot, and there's nothing I can do but pull off the road, shut off the truck and have lunch. After it sits for a while, the controls sometimes work the way they're supposed to.

    Does anyone have any cure. Any help is greatly appreciated.
  • I have a problem. My heater takes about 15 minutes to get warm and it works for five minutes and then it gets cold. It seems to get warm when the engine rpms go up but cold once they go down. I had a chevy shop look at it they said I was a gallon low on fluid, they filled it tested it for leaks (none) and it worked for about a week. Now I am back to square one. I don't want to take it back and say the didn't fix the problem because it was in for another repair and i mentioned the problem and they didn't charge me for the fluid or the test. Help, I live in Oregon and it's getting cold!!!
  • obyoneobyone Posts: 8,054
    it worked for about a week. Now I am back to square one.

    Do you mean you're low on fluid again or that the heater works for 5 minutes then gets cold or both?
  • I am not low on fluid now. It blows hot for a few minutes then cold for a few minutes.
  • obyoneobyone Posts: 8,054
    Have you checked the actual radiator or just looking at the overflow tank? If not filled correctly, you could show a full tank while the radiator is less than full. Just a thought. Oh and if you do check the radiator please make sure the truck is cool before doing so.
  • Does anyone know where all the HVAC acutators are? I think I've id'ed the driver's side temp door actuator (above the hump); the px side (on top of duct just below dash; and the mode actuator (driver's side, above right knee & towards center). Is there a 4th actuator, for recirc/fresh air door? is there some sort of 'master actuator', ie, is there a temp door 'upstream' from the driver's side and px temp doors? Also, replaced thermostat, nice hot air for a couple of days only.

    Thanks, Wick
  • ok so I figured a few things out. I was wrong when I said that I am not low on fluid. I was. Am I supposed to fill the radiator up to the fill line in the overflow tank? If so, the dealer put a gallon in and I put a gallon in and it is still not showing in the overflow tank. It blows hot now though which I am thrilled about. There are ZERO signs of leaks, nothing in my driveway and the dealer last week pressure tested it and it was good.

    thanks to all for the help.
  • obyoneobyone Posts: 8,054
    The problem is that the filler hose needs to be primed similar to siphoning. It needs to be filled with coolant so when the radiator overflows, it will flow into the overflow tank.

    How I used to do it was to fill the radiator till the brim, start the truck and wait for the coolant to drop and start to circulate (thermostat open). I then top it off again and notice it will slowly start to overflow. At that point I capped the radiator. It will usually flow enough coolant to push into the overflow tank. You should have some coolant in the recovery tank to make it easier to prime the overflow hose. Gee I hope this makes some sense. My explanation that is.... ;)

    Glad your heater works.
  • I have a 2004 GMC Sierra that has this problem, I am NOT going to pay that kind of money to have it fixed. Have you found the fix for this? Does anyone out there know the answer, it seems this is a fairly common problem but no real answers yet. HELP!! :cry:
  • I have dual temp controls on my 04 silverado. The drivers side only blows only cold air now. I replaced the temp control, but that was not the problem. Any ideas?
  • I hope someone can help, I live in Florida and the heat blowing out whenever the truck's moving is terrible.
  • jimorjimor Posts: 1
    Have a 2003 GMC 1500 and the heater is not hot enough. I've changed the thermostat twice, flushed cooling system, topped off fluids. It circulates through hose. Heater hoses are warm but not hot. Clutch fan disengaged. Heat temperature is between 100 & 105 degrees. Don't know what else to check. Thanks!
  • My 1996 1500 Silverado's heater blower and radio most of the time will not start when switched on. After driving for some time they may activate. They usually come on together but the radio will fade out but the heater continues to operate. After turning engine off the whole process starts all over again. The problem is similar but they donot correlate together. Thought it might be a common ground but have no idea what to do. Thanks
  • dmoshdmosh Posts: 3
    You may have a leak only when the temperature is between cold and hot - watch what happens as the vehicle is warming up. Had on like this once -
  • dmoshdmosh Posts: 3
    After driving in snow my heater blower does not work the next morning.
    It appears to thaw out from engine heat after several hours - not really sure.
    Drove briefly this morning in snow - now blower does not work again.
    Anybody else experienced this.

    Blows snow when on defrost too!! Not good
  • My dealer fixed my draft on the passenger side by resealing the cold air intake for the heater. I beleive they removed the windsheild cowl cover and wiper arms to get at it. I could not see that they did anything inside the cab. It only cost me $112. Hope this helps.
  • c64usc64us Posts: 1
    My problem is a little different from those posted here. I have 2002 2500HD LT, Duramax, with climate control. My AC will work great when it is hot out, but when is is cold, and the windows are fogged up, I cannot get the AC to come on. When I push the AC button it will blink a couple of times then shut off. I would like the AC to come on to help with de-fog. Any suggestions?
  • jborgojborgo Posts: 1
    I was having the same problem with my 2004 2500 Silverado and the dealer replaced the controller along with a modulating valve. I was told the controller was not sending the signal to the valve. Then after the controller was sending the signal the valve was not responding. This is working normal however I have an interment problem sometimes un-commanded hot or cold air starts coming from one side vents only. Going back to the dealer next week.
  • Thanks for the info. I knew something had to be leaking somewhere, and I couldn't find it just looking under the hood or in the cab. It might just be worth a $100 bucks or so to have the dealer take it apart.

    What gets me is, there seems to be a lot of people with this particular problem. But if you take it to a dealer, they act like they've never heard of it! Thanks again for your help.
  • A plastic or some type of composite sleeve has broken on end of the heater core where the hose connects.

    I have been unable to find out from dealers or part stores whether or not this piece is actually a part of the heater core or if this is something that can be purchased separately. Actually I haven't found anyone yet that is familiar with this piece.

    Would you happen to know what this is called,? and whether it can be purchased separately or if it is actually a part of the heater core?
  • obyoneobyone Posts: 8,054
    Are you writing about an off white cylindrical shaped clip that depresses to release the hose from the heater core?

    If so it is sold seperately from the heater core.
  • ZULALA, I have the same problem in a 2001 -- did you find out what was causing the problem. I would surely appreciate help if you found any.

    If I ever turn dial to the hot side - It stays hot "full hot" and will not change... The AC - - everything blows Hot only regardless what I try.
    RDT
  • I just wanted to ask if you found an answer to the all hot or nothing you described here.... I have a 2001 that does the same thing.... If you turn the "hot" control - that is all you get - and you can't turn it off. It has done the same, in that, I have shut it down and everything work when I started it up a few minutes later... I have not seen or heard anyone that actually figured out the problem - and surely would appreciate learning what and how to fix it -- if anyone knows.

    Thanks
    RDT
  • Good News! I have a 2001 and finally got this one figured out with the help of my local mechanic.(the dealership never could diagnose the problem) The operation of the lower actuator that opens and closes the the blend door was intermittent.When it would stop in an open position the heat from the heater core would continue to pour in and make it unbearable. Shutting off your vehicle would resetw the actuator to it's home position. This also explains why my AC wasn't always cooling efficiently during the summer months. The actuator costs about $65. To access the actuator remove the air box cover underneath the dash and it is located just to the right of the console. Piece of cake! Hope this helps.
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