Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

GMC Yukon AC and Heat Questions



  • rayb6rayb6 Posts: 1
    Picked up vehicle last Sunday with 300 miles on it. When I restart my 2007 Yukon xl (Not Denali), my heat only comes on after I change the heat settings a few times. The temp gauge is up to near 210 but no heat. I have to adjust the flow direction. Went to the dealer yesterday and they said it was normal. Any suggestions would be helpful.
  • jlflemmons-

    Thanks for the great tip! I recently replace my battery on my '04. Well, when heater is turn on the passenger side blows Hot air but, the driver side blows Cold air; "very cold".

    I called the dealer and they didn't have a clue but wanted to keep my GMC for a few days.

    I think your reprogramming will reset the system. . .thanks --Los Angeles, CA
  • Mine is a little different than everyone elses. when it's cold out.. say in the 20-30s it takes forever for the defrost to start blowing... either hot or cold...

    in the summer sometimes it takes mins. before the a/c will blow....

    no problems with air temp.. just the time lag for it to blow any air at all...

    anyone have a clue?
  • This sounds kind of like my problem with the 01. Due you have the auto climate control? Does the rear blower work, even if the front one does not? Let me know this, and if this is the case, I might be able to help you.
    Lyle Pfeifer
  • yes.... rear works as designed and the front is the only one that gives me problems. it has auto and i'm tried the fuse reset... maybe i'll try it again just longer.

    ok this morning it was cool 45degrees and it took awhile to come on. now it's 65 and it will turn on real quick... if it's 100 the a/c will take awhile to blow

    but rear air is normal in all aspects
  • :cry: come on now?????? nobody has any ideas?????
  • tidestertidester Posts: 10,059
    Maybe the fan is "gummed up?"

    tidester, host
    SUVs and Smart Shopper
  • not sure... it works and works well.. but, it has to finally decide to turn on and once it has been going for awhile it will turn on instantly.
  • Do you have dual air/heat?
  • There is a plug that goes into the AC/heater fan. You have to remove a cover that is held on with 3 or 4 screws and you can see the fan motor. This cover goes from the passenger side all the way to the middle of the tunnel. The plug is on the right or inside of the fan and kind of hard to get to and remove. The fan is located on the passenger side of the car, the plug, if like mine is shorting out. It is connected to a box or block, similar to the resistor block on a non auto climate control unit. Yours runs about $130.00. I replaced mine as the plug melted due to being installed wrong. Look inside the plug for bunt contacts. One of mine, the main power point was pushed all the way down and did not spring back up to allow good contact, causing a high resistance and heat build up causing the plug to melt. If you pound on the cover about 1 foot over from the passenger side wall with your hand, your fan should start. But remember, this plug is getting hot. This is at least what happened to mine. Worse case, if you need a new plug, you have to buy the harness just to get the plug, I think they said about $165.00.
    Hope this helps. Let me know, as I had this problem with a 2001.
    Lyle Pfeifer
  • thanks for the info... i'll check it out and let you know if it worked
  • i have dual zone in front and rear air/heat in the back. I will take a look at the plug this weekend if i get a chance.
  • Well guys,

    I remove the fuse and waited few minutes before replace it.

    It didn't work. I still have cold air blowing on the drivers side and hot air blow from the passenger side/. Any Ideas
  • Hey guys!!
    I have a GMC Yukon XL ’02 and it was fine with me until today, I drove to work (it’s about 20 minute drive) and after I park it I turned it off, then suddenly the AC turned on as if it on Auto, I tried ever thing to shut it down I remove the large gray fuse and small 10amp fuse under the hood and the AC still works I turned the SUV on and I couldn’t even control the AC it seemed it has a mind of it's own.
    finally I unplugged the battery and guess what … it works the damn thing went back to normal. my question is what the hell is wrong with my SUV… !!????
  • tidestertidester Posts: 10,059
    Are you sure it was the air conditioning that was running or was it just the air conditioning fan? The fan will run off the battery/alternator which suggests that your fan switch is faulty. The compressor does not run off the battery.

    tidester, host
    SUVs and Smart Shopper
  • no it was the fan only ... well thanks a lot pal... it seemed that the fan switch is damaged... :)
  • All of the rear air vents push out cold air where as the front control works just as it is suppose to. Is it a matter of resetting the computer or is it mechanical. The dealer wants $900.00 to possibly fix the problem?
  • I have a 00 denali yukon and the heater does not work properly all the time. Please let me know if you have experienced any of these problems with your vehicle
  • obyoneobyone Posts: 8,054
    You could disconnect your battery for 15 minutes to see if it resets. After I had replaced the rear evaporator core, the system needed to be reset for the rear controls to work correctly.
  • obyoneobyone Posts: 8,054
    Try and check your coolant level. If the level is low the heater will not operate correctly.
  • rkg1rkg1 Posts: 13
    Has anyone else had this problem? We will get hot air blowing thru the front defrost vents (on top of the dashboard, right under the windshield), with all temp controls OFF.

    We recently figured out that if we turn the A/C on and let it blow really cold air thru the regular front vents, then turn off the system - that the defrost vents will stop blowing the hot air.

    Any advice????
  • I'm having the same problem in my 2007 Yukon. Started almost immediately, been serviced two or three times...once they said they couldn't duplicate it so, out of luck. The next time it happened I drove directly to the dealership and they said how strange it was, they needed it overnight and said they replaced or adjusted some type of actuator or something. The next time they said they'd need it for a while to try to figure it out, as they were "stumped". By this time fall was coming and we haven't used the AC until a week ago...same old problem---cold as ice on driver side and hot hot air on the passenger????
    Did you ever get an answer for this on your Denali?
    I am one more visit away from a Lemon Law Action... Thanks for any tips!!
  • I had the same problem on my 2004 Yukon XL. The HVAC worked fine in front but the back and overhead only put out cold air. It was fixed for free under warranty but it only took 20 minutes. They said that there was a bad connection.

    Since then all of the A/C quit working. They charged $325 to reprogram the HVAC system. They couldn't adequately explain what was broken or what failed, it just need to be reprogrammed. My service contract did not cover this so I had to eat it. Not happy.
  • Does the A/C computer control the heating as well, will pulling the AC fuse do the same for the heating?
  • rkg1rkg1 Posts: 13
    That's a good question.

    Don't know the answer. Sorry

    When my defroster blows hot air (with all controls in the OFF position), I turn ON the a/c and let it blow cold thru the defroster and floor vents for a few minutes. Then i turn everything OFF and it stops the defroster from blowing the hot air.

    Can't figure out why it's blowing hot air on its own, and I have no idea why blowing the a/c and then turning everything off, works either. ????
  • moterymotery Posts: 5
    the same thing happened to me but i unplug the battery well that stopped it but now when i turn the A/C on the air is cold in the back but in the front it's wormer not hot but little wormer then the back ...

    my mechanic said it might be fuse or a switch( I forget exactly what he named it) under the dashboard and it will cost me 200$ to fix it ... I’m confused now i might try you way and see what happen... you never know… :D

  • tjustustjustus Posts: 1
    I am having the same issue... My rear climate control will blow out cool air, when I'm calling for warm-hot air. What came of your situation?? Also has anyone else had a similar issue and what was their experiences??

    A separate issue... While blowing A/C the front vents start blowing HOT air. I have to turn the vehicle off for this to stop.

    Problems we should not be having for this type of automobile.
  • moterymotery Posts: 5
    they say it’s common problem for this kind of Suv’s after a few years on the road. Well i say Bull S**t.
    Anyway, there’s a “cheap” way to overcome this dilemma … you see the hot air pipes (there are two pipes coming from the compressor going to the firewall, you’ll find them on the right back corner two black rubbery pipes next to each other) these pipes are responsible for the hot air flow in your a/c when you disengage them use sparkplug to plug it, make sure it's pluged (don’t put it back in just set it away from any moving parts) that will stop the hot air and you’re a/c will start to get cooler than before, you put right back again in the winter.
    OR, you may unplug the battery for 10 min. then put back and see if the a/c is working well or not keep in mind that the ignition key must be on START during this process.
    Good luck,
    Note: you can do it yourself on a Sunday it will only take 20 min. to do it.
  • stearnspkstearnspk Posts: 2
    Over the past three years we have had freon added to the system and each time we add a small amount it stays cold for a period of time. Each time this period of time is shorter. The last time it stayed cold for about 3 months only. The last two times the mechanic added dye to the freon and both times could not find a leak. Any possible solutions.
  • moterymotery Posts: 5
    have you ever inspected the climate control fuse it might be a bad electrical problem, any way i'm going to share your story with some of my friends so give me some time and i'll get back at ya... good luck. :shades:
Sign In or Register to comment.