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GMC Envoy Heating Ventilation and Air Conditioning



  • im having the same problem when i turn on the a/c the engine starts to strumble like a yo/yo and then it goes dead it those start back up but as soon has i turn on the a/c again it starts to do the same please let me now if you now the problem for this
  • julie316julie316 Posts: 1
    My Envoy has recently started doing the same thing. Have you been able to find out what was causing your AC problem?
  • ttenczattencza Posts: 4
    there is a drain tube probably on the firewall where the blower is. use a small probe that will fit inside, but do not force. there is usually some debris blocking the drain. Again... do not force the probe just move it lightly as to not puncture any thing. this should start water to drain.
  • rcorkrcork Posts: 1
    Yea this is correct. look down by the passenger side bulk head between the engine cooling system expansion tank and the engine itself you will see 2 insulated pipes wrapped in a silver material, just to the right if this you will see a black elbow or elbow and pipe coming out this is what blocks simply remove and clean the pipe and and you should be able to clean the elbow by simply squeezing it. if it is blocked the amount of water released is astounding. it literary takes less than 5 mins :shades:
  • ttenczattencza Posts: 4
    My 2004 ENVOY XL has the same "No Blower" Problem. I bought 2 Blower resisters from 2 different sources, both saying "exact fit". The problem is it does not fit. All the replacements so far have a 7 pin connector, but the one in the car has only 3. Can someone please explain if there is a conversion to upgrade the 3 pin to a 7 pin, or is there resistor with 3 pins out there?
  • jaesjaes Posts: 1
    My 04 Envoy is now having the same problem did you find a solution
  • My 2004 Envoy is doing the same thing. Works great at first then after about 20 m- 30 mins stops blowing cold air. Did you get yours fixed? If so what was the problem?
  • techimantechiman Posts: 3
    So I have checked with a meter and once the engine and works heat up the clutch quits working and the AC gets hot, I have put the meter on there and it shows 13.7 volts but the clutch does not spin, Is it possible to change the clutch or does it need a new compressor?

    and is it possible to do any of this without removing the engine or Rad and fan as there is very little clearance in there I had enough trouble getting the connector apart to put the meter on it.

    Thanks in advance.
  • ttenczattencza Posts: 4
    It was the Blower Motor Resistor. Every part store has a so called OEM replacement that has a 7 pin male connector and a output to the blower motor, unfortunately My 2004 has a 3 pin connector and a output to the blower motor. I got the exact part by goint to a GMC dealer and they searched for the part by VIN number. Bingo... exact fit, but it cost $119 dollors. I bought 2 of the wrong parts for $57 and wasted my time and energy shipping them back. Take my advice... go to the dealer first.
  • ttenczattencza Posts: 4
    It was the Blower Motor Resistor. Every part store has a so called OEM replacement that has a 7 pin male connector and a output to the blower motor, unfortunately My 2004 has a 3 pin connector and a output to the blower motor. I got the exact part by goint to a GMC dealer and they searched for the part by VIN number. Bingo... exact fit, but it cost $119 dollors. I bought 2 of the wrong parts for $57 and wasted my time and energy shipping them back. Take my advice... go to the dealer first.
  • parlaneparlane Posts: 1
    2003 Envoy XL- To all you users who have issues with the blower not turning off (A/C), it is the module that is causing the prob. We had our dealer pull the fuse under the middle seat. If we need to use it, we can then replace the fuse and pull it when we are done with it.

    Has anyone had an issue with the top of the rear lift (the part that holds the rear brake light) coming off? We were driving down the highway and it totally blew off. The rear hatch window is still intact, but will most likely break when they try to straighten the mounts that are attached to the window. Have had no accidents or vandalism to the car.
  • rdd21rdd21 Posts: 2
    I am having the same problem with the dash vents not working, also my outside temp always reads 50, I saw the answer to this problem but does anybody know what to do to get the air to blow out of the front vents?
  • gmcustsvcgmcustsvc Posts: 4,251
    I would recommend taking the vehicle to the dealer. They will be able to assist in getting the vents operational.
    GM Customer Service
  • I have an 04 envoy that will blow cold air initially, then after a few minutes it will shut off and blow warm air. I have changed the ambient air sensor, thermostat, engine fan, blend door actuator on passenger side, and no change in symptoms. for the few minutes it works it works fine, then compressor will shut off. any answers?
  • rdd21rdd21 Posts: 2
    Thank you, I'm sure the dealer could fix with a large bill. I was hoping to hear it was an easy fix I could do myself.
    I am surprised to hear the Envoys all having the same problem and GM does not recall to fix the problem. With so many different Envoys having the same problem it's obvious this is a faulty part. After doing some research for my current problem, I have learned other issues I had fixed (my clutch fan replaced and the entire electrical system going out) have happened to many other Envoy owners as well. I realize when a vehicle gets old things start going bad however, if the same issue/problem comes up with so many different Envoys it's pretty obvious there is a problem with the part.
    I even found a website stating the problems that have come up with the 2002 Envoys and what to expect if you buy one. The clutch fan and electrical problem were the #1 issues!
  • olson8olson8 Posts: 3
    Sometimes the A/C comes on, then shuts off and only blows hot air. What is the problem?
    A/C Expansion Valve? Ambient Air Temp Sensor? A/C High Pressure Cut-out Switch?

    Anyone have any ideas -

  • I have the exact same problem...did you find any answers?
  • olson8olson8 Posts: 3
    Not yet,still researching. will post when i get this figured out.
  • concannon1concannon1 Posts: 3
    edited August 2011
    I spent a few hours on this and have it figured out. Very common problem. Here is an answer that I found that sums it up:

    An occasional problem on this vehicle is the failure of the A/C Low Pressure Cycling Switch. The cost to replace the A/C Low Pressure Cycling Switch is estimated at $43.19 for parts and $32.50 for labor. All prices are estimates based on $65.00 per flat rate hour and do not include diagnostic time or any applicable sales tax.

    I followed the instructions and jumped the wire (bypassing the low pressure switch) and it totally worked. I could almost twist this part off by hand. I am going to pick the part up at the dealership tomorrow. I had the part off and back on again in about 30 seconds.

    Here is the a very good link that i started with. Good picture of the part. Wish I had known this last week when it was 100 degrees! 90's this week though...
  • I was so confident that i had the answer. My symptoms matched. I even jumped the wire and the a/c started working. I am pretty sure that was just coincidence. My a/c is still intermittent. Comes on cold sometimes. Last 20 minutes sometimes, 1 minute or not at all others. Really hoping for some answers. Hate to take it to the dealer. Any suggestions?
  • olson8olson8 Posts: 3
    Took the Envoy to a local garage that the NAPA owner said would be a good shop.

    The Owner/Mechanic found out that my AC was low. Had 2.1 psi and needed to have 3.0. All checked out ok.

    Good luck. Spent 92 dollars.
  • When using my airconditioner with the air blowing through the dash vents, my 06 Envoys' air blows cold air on the passenger side only.
  • I have a 2004 GMC Envoy that blows hot air. I had tried to recharge the Air thinking that was the problem when the canister was cold but the air still remains hot. I'm lost. Does anyone know what the problem is?
  • I think by now GM needs to step up and at least provide some answers to some of these questions and problems that most of us are having I'm pretty sure that most and all of these issues have been addressed at some point and have been worked by GM dealers. Obviously they don't care about their product since they've made their money off the sale. If they don't want to lose money by calling or recalling these vehicles they should provide the answers of what it takes to fix these pieces of crap. :lemon: :mad:
  • Oh I forgot I also have the AC problem where the air does not blow out the front vents, I've tried disconnecting the battery and nothing happens I verified all the fuses. Oh and also just repaired the stalling/hesitation... it was a dirty throttle body pretty simple fix that no mechanic understood how to repair. I still have to get the measurement cluster panel replaced or fixed. This is unbelievable amount of problems everyone's having it with these vehicles...GM really sucks! :mad: :lemon:
  • Hi All!

    04 'Voy SLT-- We had the same issue with the AC/heater blower working intermittently and not shutting off. In my 45 years in working in, under, over, etc with cars, I had never experienced any electrical accessory not shutting off when the key was off and out of the car!

    However, thank God for these type of Internet forums. If it wasn't for them, we would be at the mercy of the dealership service centers and/or repair manuals. The former will all know rip us off, sometimes not solving/remedying our car woes. The latter do not always explain details about a repair, teardown, and/or re-assembly well enough for first-timers or DIYers.

    With the help of you posters, I ordered ACDelco Part #15-80567, Heater & AC Blower Control from Rock Auto for a cost of $73.79, plus $5.65 USPS Priority Mail shipping charges to Southern California. By week's end (Fri., 8/26), I had the part in my hands. Fast shipping, as the part was shipped from Wisconsin.

    The install was quite simple.

    Remove the plastic kick panel (the one that surrounds the two round "drain tube" ends facing your passenger's feet) under the glove box (two hex screws on each end. There are three socket couplers that are attached to this panel that you will have to work out of their holes. They are quite troublesome (I hate these type of "one way, push in attachers) to take out without damaging them. Once you get the 3 couplers unattached, you simply take out this panel and place it aside.

    You will be able to see the switch, which is attached to the blower cavity from below. The switch is visible when you look up toward the windshield from below the glovebox. It will have a 3-wire male socket attached to it's face (the face bears a 3-wire female socket) that bears a white part number label to it. Leading from the switch is a 2-wire (black and violet colored wires) male connector.

    There is a spring retainer that holds the glovebox in the open position (so it won't drop on your passengers lap when opened) that you must spring bend up to let the glovebox drop down so you can gain access to the 3-pin connector that is attached to the blower motor itself.

    Incidentally, the cars with ATC take the 3-pin connector switch, while the manual control AC cars will take the 7-pin switch.

    After dropping down the glovebox, you will see the 2-wire (black and violet) switch connector. Again, this connector type can be quite difficult to separate without damaging it, so be careful. Once you separate this connector, you should then close the glovebox and look for how the switch is attached to the blower cavity.
    The switch is attached with two hex screws. A 1/4" ratchet drive/socket set is a must for this whole project.

    Once the two screws are out, the switch will drop down and it is a simple matter reassembly in reverse order.

    It took me about 30 total minutes for this whole operation and the AC works as good as new!

    No comment on why this part failed so early in this 'Voy's life, it only has 54,000 miles on it). My Honda CRV has 190,000 and hasn't had any electronic issues (or otherwise) other than a factory recall/replacement of the ignition switch).

    Is it true that Japanese cars are more reliable and error-free than Detroit products?

    I do have pic's of the switch and part number on the ACDelco box in case anyone is interested. But I do not know how to post pic's on this web site.
  • ralsocalralsocal Posts: 2
    edited August 2011
    Unfortunately, you (mikejp20) have a valid point on the domestic v. foreign debate.

    My first car was a 1955 Chevy Bel-Aire V8. My second was a 1966 Pontiac GTO... And I've had various other Detroit products in my garage over the years. The sixties and previous were the days during which the Big Three were riding high. Oh, of course, there are those divisions within each of the Big Three that have consistently produced good products (Cadillac and GMC Truck Division are just two examples).

    Detroit, in general, would gleam with pride when airliners full of Japanese executives, engineers, and technicians would fly to Motown to see how Detroit built cars. The Japanese teams would then fly back to Tokyo and improve on what they saw in Detroit. The rest is history. All that those old fogies that ruled the Big Three were interested in is fattening up their bank accounts. We eventually lost the war.

    I currently own six autos. Two are Japanese, one German, and three American (all classic era cars). The Japanese cars (Honda CRV and Toyota Tundra) are by far the most reliable, followed by the German car (a classic 1986 VW Cabriolet). The three American cars ( a 1990 Komfort motorhome on a GMC P-30 chassis, a 1968 Dodge Charger RT, and a 1965 Pontiac GTO) are all from classic eras during which Detroit built cars well and reliable.

    Obviously, we all know what kind of cars Detroit was building in the 70's and 80's. And, we all know that Detroit found themselves at a crossroads demanding that they build reliable cars near equal to products out of Tokyo, Munich, Berlin, and Seoul in order to survive in today's marketplace. Detroit is nearer equal, but still has a lot to makeup, if it ever will to ward off the competition over the globe.

    The issues with the AC in Trailblazers/Envoys listed in this thread all point to what GM is still building AND THERE APPARENT LACK OF INTEREST IN SOLUTIONS FOR CURRENT OWNERS! Do they honestly think that people who are having these issues will ever buy these products again? Have they forgotten how badly Tokyo, Seoul, Munich, and Berlin buried them. Chrysler, GM, and Ford are but shells of what they used to be.

    And, those old fogies that used to run the Big Three? Well, they laughed all the way to the bank. They are now in their mansions, on their ranches, and/or on their yachts enjoying their millions--which, quite frankly, all they really cared about...
  • My 2006 Envoy is doing the same thing...passenger side only is cool, warmer air on driver side. After awhile, even the passenger side gets warmer (on hot days). Did you get your problem solved?
  • gmcustsvcgmcustsvc Posts: 4,251

    Were you planning on having the vehicle fixed by a GM dealership? Please keep me posted.

    Thank you,
    Caron, GM Customer Service
  • I have a 2003 Envoy XL, 116K miles.
    Yesterday as I was driving I noticed that the AC blower speed was not changing as I pressed the buttons to change speed. If you shut the entire climate control unit off, the fans continue to blow through the defroster. This happens even after you shut the vehicle off and pulled the key out of the ignition.

    The only way I found to shut the blower off is to remove the fuse under the hood.

    Is this a blower issue or is it in control unit itself? What can I do to narrow down the possible causes and/or solutions? Thank you for your help.

    I would love to see the pictures that you have so that I know what I'm looking at as I diagnose this issue. It sounds like I may have to order the same part.

    Thanks for everything.
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