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Chevy Silverado and GMC Sierra Climate Control



  • dwhite456dwhite456 Posts: 5
    read through all the posts...all of them.

    Have problem with suburban blowing hot through all vents. Have front and rear heat/AC controls. Single controls for right and left.
    2 summers ago AC started blowing warm in front but still a bit cold in back. Ran some new refrigerant in it. It wasnt really low but still put some in and the level remained in the normal zone. Air blew cold again for a while.

    Last summer air was blowing hot again, now this time it was in both front and back. bought another can of refrigerant. Same deal...wasnt really low but put some more in. Air blew cold for about 2 weeks then stopped.

    Need help troubleshooting to root.
    What I know is that the compressor is spinning as I can see it turning when on. Cant really hear any clicking or anything indicating the system is trying to cool. What else can I check to try and narrow the problem down? i can leave it running with ac set to on and I dont see any condensation on any of the metal lines under the hood. I also checked all the fuses and relay and didnt see any problems. Did the pull ac fuse under hood reset thing and nothing came from that.

  • obyoneobyone Posts: 8,054
    You have a leak resulting in refrigerant loss. You can add dye which comes with some of the refrigerant at most parts stores or you can save yourself the headache and take it to a shop.
  • dwhite456dwhite456 Posts: 5
    edited June 2011
    I dont think I have a leak as each time I shot some more refrigerant in there it was in the normal zone. I just shot enough to take it to the top of the normal zone.

    Today I check the actuator that is over the hump on the passenger side. Everything checked out and the motor was moving and it was operational.

    I appreciate you replying
  • obyoneobyone Posts: 8,054
    The a/c system will run warm with low refrigerant and cool when more is added definitely has a leak. Might be a slooooow leak but still a leak. Another indication of low refrigerant is the constant recycling of the compressor.

    I had a '02 Denali and though I added the dye, I couldn't find the leak. That is until I checked behind the passenger rear tire and found what appeared to be a plugged drain hose. Unclogged the hose and a ton of water and dye spilled out. Apparently, the clogged hose cause the rear evaporator to fail and leak.

    Course another possibility could be in the temperature control. Not sure if you have auto or manual. Still comes back to the a/c working when more refrigerant is added.
  • dwhite456dwhite456 Posts: 5
    edited June 2011
    thanks, I will check for a leak and maybe add the refrigerant that has the dye in it.

    I have manual AC. Is the temperature control the actual circuit board behind the manual dials?

    I got down and looked behind the back rear passenger tire. I saw what looked to be like a black rubber thing. Didnt know if that was the nipple that people are talking about?
  • obyoneobyone Posts: 8,054
    The black drain tube in back of the passenger rear tire looks like a rubber piece with a 1/2" slice in it. A flat head screw driver would be perfect to open it a little and see if you have water accumulating in there. Careful not to be directly below it when prying.

    I'm assuming this is the controller that you're referring to. Yes it does have a board in it.


    How long is the time period between topping off and the unit blowing warm air?
  • dwhite456dwhite456 Posts: 5
    Last summer when I shot it with some more refrigerant it blew cold for about 2 weeks and then it went back to blowing air temperature again.

    Yes, that is the manual controller that I have. You suggested maybe it was a temperature control problem. Is replacing the controls or the circuit board the solution for a temperature control problem?
  • obyoneobyone Posts: 8,054
    Is replacing the controls or the circuit board the solution for a temperature control problem?

    Of the controllers that I've seen fail, about 90% was the fan speed control switch and the other 10% was the directional control. Never seen a failure of the temperature control but it is possible.

    While there is no "standard" time between refills, two weeks would be a reasonable amount of time for a slow leak. The last time I had a leak it was three months between refills so I didn't bother to fix and traded the truck instead. When I had the leak with the Denali's rear evaporator, the hole was so large that trying to top off with R134a wasn't an option as it would escape as fast as it went in.
  • 5five5five Posts: 2
    I have the above vehicle with the digital dual climate control system.

    I am experiencing problems with the driver's side blowing hot air while the pass. side remains cool at various times.

    I have checked other forums and have found ideas but no answers. When I pull all my HVAC fuses, the problem corrects for a short period of time but when shut off and restarted returns.

    I have had the dealership reflash the HVAC computer and I am still experiencing the same problems. In fact they told me that all of the "old" model year problems have been fixed.

    I know it can't be faulty blend door actuators or it wouldn't go cold at all it would be locked in position.

    I know it has to be some sort of computer/electrical issue since pulling fuses fixes it temporary 75% of the time.

    Any suggestions? I am out of warranty..... :(
  • gmcustsvcgmcustsvc Posts: 4,252
    I apologize for your frustrations. Has the dealer tried to envolve Technical Assistance? I look forward to your response.
    GM Customer Service
  • dwhite456dwhite456 Posts: 5
    Put some more refrigerant in it and it is still the same. One thing I did notice.....The AC pump was spinning but it didnt seem like it was cycling. After putting some refrigerant in it at least started cycling albeit did sound a bit rough or strained.
    Any other ideas or suggestions where to troubleshoot?
  • obyoneobyone Posts: 8,054
    If the compressor didn't cycle until you added the refrigerant it is safe to assume the level was really low. By adding the refrigerant it started to cycle meaning that it had enough 134 to start cycling. It would usually be a fast cycle until you reach around 1.75 pounds of refrigerant.

    Were you able to add the dye?
  • codbrwncodbrwn Posts: 1
    I saw your post and have the same problem, have you found an answer yet? Thanks
  • i changed the resistor located on the blower motor and that was it!
  • dasani3dasani3 Posts: 2
    hey there...there should be two fuse panels...when you are sitting in your drivers seat there is one on the left side of the dash by your leg... you will need the drivers door open to see this... pull the panel off and on that panel there in i diagram what fuse is where and what its for... check that.. and then under your hood on the left side... this is a large square box pull the top off and do the same... i hope this info helps you
  • dasani3dasani3 Posts: 2
    i checked the plug in connection for power there was no power... all fuses and relay is fine... my ac is fully charged... is it the switch inside the next thing to look at.... how do you test the switch to see if it is working.... thanks
  • one2manyone2many Posts: 1
    I have a 2005 2500HD 4x4 and the blower fan cuts in and out when set on 3 if it cuts out i can tap on the duct n the passenger floor and it will return working. I was told that it was the blower resistor module and I went and bought a new one from autozone it costed around $60 to $65. I was also told it was a comon part to go out so when i took everything apart and got to it i noticed the plug on the end of my harnes that plugs into it was also burned so i taped up the burned wires to prevent it from burning any more and my conections looked good enough to work till i could find another plug so i put everything back together and it worked fine till i hit a bump then back to the way it was. So as for mine I believe the plug needs replaced to fix it and if yours is burned just a little and dont have a firm conection or is loose just a hair i would recomend starting there first its cheeper. As far as finding the plug i havent yet I was gunna try my local junkyards and probably pay $5 or $10 but they dont have anything that new so in waiting for them to get one but for now i keep something to reach and bump the duct when it goes out then its fine till the next bump. I know this Is long and drawn out but I hope it helps you
  • AC quit blowing on super-high, have been told this could be the recirc gate not closing. How do I test this and other gates, have been told that my truck might have three or four gates with motor actuators. Anybody have a diagram? I'm not very electrically inclined so please keep it simple as possible? Thank you in advance for your help!
  • there has been a recall on these vehicles ac not working. it is nearly impossible to find but i have uploaded the recall on my website. gm will replace for free.

    Models: 2003-2006 Chevrolet Avalanche, Suburban Tahoe

    2003-2007 Chevrolet Silverado

    2003-2006 GMC Yukon, Yukon XL

    2003-2007 GMC Sierra
  • gm did a recall on this. i put the link on my website cause gm makes it almost impossible to find.
  • I keep trying this link but am unable to get access. I have a 06 2500 HD the dealer replaced the part once then I had it replaced a second time at a cost of $400. plus.
  • The link is back on line. I create websites and had a demo site on line. Have a great day
  • Link is back online.
  • Great post and glad to see that recall. I DL'd the .pdf and posted it up on Diesel There might be a few of the 125,000 truck guys there that might find that interesting.

    Heres one for all. 2006 Sierra 2500 HD: in 'winter - Drivers side blows cold air - Pass side is normal at whatever temp setting is. Is this my mode actuator or a blend door actuator issue...or could it actually be the reflash that my truck might or might not have gotten.? Build date is Oct 05.

    To date I have simply (in winter time only), disconnected the batts for 5 min or so, turn key on and let system calibrate..worked all last year but a PITA when its -40 out.

  • My 2000 Silverado 1500 Climate Speed Control does not work on the first 3 speeds. It does work on speeds 4 and 5. Where or how do I trouble shoot the problem?
  • obyoneobyone Posts: 8,054
    You could buy one off of ebay.

    a/c controller

    Or remove yours and replace the diodes on the speed switch.
  • rayt2rayt2 Posts: 1,208
    Been a long time since I posted here but I still have my 2000 Silverado 2500 2wd excab shortbed.
    Here is the scenario: Parked truck for couple of days. Last night could not unlock door with key fob, OK use the key. No dome light, no start, no nothing evrything was dead.
    Hooked up battery charger, as soon as I powered up charger dome light came on and the defrost is running fullspeed with fan control set for "off", temp setting on midrange and source setting on "floor".
    I have no clue what happened or caused this.
    Any suggestions/help appreciated.

    Ray T
  • dhb4dhb4 Posts: 4
    I recently bought an 06 gmc sle and have been having trouble with the dual climate control. When I have the ac on or even just have the fan blowing with the temperature setting on cool. The driver side will start blowing very hot air and the passenger side vents are normal. When I turn the truck off and start it back up, it is fine for bit, and then it will do it again.
    Anyone have any ideas?
  • 5five5five Posts: 2
    No matter what setting, the driver's side would creep up and become hot.

    I tried every fix found on the internet and ended up going to the dealer who replaced the driver's side blend door actuator at the cost of about $400.

    It was fixed in late June and I haven't had a problem with it since.

    Good luck.
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