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Pontiac Grand Prix Climate Control/AC



  • ocmike3ocmike3 Posts: 232
    It is probably a resistor on the fan control board- I had the same thing happen to my Canyon. It was fixed under warranty and the invoice stated they changed a resistor.
  • qi2001qi2001 Posts: 1
    I have exactly problem today, only level 5 is working. Wondering how much they will charege me ? :sick:
  • In the switch for your ac/heater blower are resistors. They tend to go out after so often. The only way, that I have seen to fix them, is replacing the a/c head unit. Unless, you know someone who is real good with electronics and can take it apart and replace them. I mean real good with electronics!
  • alcanalcan Posts: 2,550
    The usual suspect is the blower resistor assembly. It's located under the right side of the dash, just to the left of the blower motor. Remove the rear screw, loosen the 2 front screws, and slide the resistor out.
  • Do they have an aftermarket version of this resistor or is it a Pontiac part only? Thanks for the help!
  • alcanalcan Posts: 2,550
    Aftermarket are available.
  • On a 1999 GP i got the rear screw, I can see one of the front screws there gold. Any pointers? Tried dropping the fan but a harness of wires prevented that.
  • My '06 does the same thing. I don't think it makes a difference unless you get one of the warmer days when it might turn on the A/C when you didn't really need it. On those 50-60 degree sunny days, I make a habit of turning it off, because I have felt it kicking out air conditioned air. Not sure why it isnt like other GM climate control systems where when you turn off the A/C, it stays off until you turn it back on.

    Mike :)
  • rayainswrayainsw Posts: 2,953
    “when I use the auto climate control and set the cabin temp to a comforable 70 degrees the air condition (AC) light always comes on.”

    I’m not sure I’d use the term ‘normal’ – but I never use the ‘Automatic’ setting – and the A/C light comes on probably 95% of the time when I start the car. Thus it appears to be operating as designed. I have not figured out why it does ** not ** come on occasionally.

    In the Summer (here in Hot-Lanta) I turn it off when I don’t think I require (or desire) de-humidification. I happen to like fresh air – and almost always, even in Winter, have my moonroof in the vent position. Now, when it is cooler, particularly in the mornings, I just have trained myself to always turn it off - again unless it is quite humid and the inside of the windows requires running the condenser.

    Just as I adjust the Temp, the steering wheel angle (I set it all the way up on exit), etc. when I start the car.

    - Ray
    Still, at this advanced age, able to learn new habits . .
    2016 BMW 340i
  • evandroevandro Posts: 1,108
    Whenever the HVAC is defogging it turns on the AC compressor do dehumidify the air blown at the windshield.
  • etcbetcb Posts: 42
    Make sense, and it is a great feature but shouldn't it shut of automatically after it dehumitfies? I'm thinking that if the compressor remains on, it reduces the gas mileage.
  • I have never actually checked, but I don't think the compressor actually engages during colder weather. You might be able to see the compressor engaged or not by looking under the hood, but not around here, the weather is warm enough that I have felt the A/C coming out of the vents if I didn't have it turned off. I didn't need the A/C, but it was still on.

    Mike :)
  • evandroevandro Posts: 1,108
    The thing is that the auto HVAC doesn't have a moisture sensor, so it just assumes that when the conditions exist for the windows to fog up, it will blindly redirect the air flow and turn the AC compressor on, just in case.

    Yes, it uses a tad more gas, but it's hardly noticeable in a 200+ HP car.
  • Hey ya'll and oh yeah, got my car fixed, the ABS/Trac/&check engine lights that were coming on and it was something to do with the rear hub, as was explained earlier on this web string. Oh and I got my shifter fixed, Hooray, Is that weird to not have to push in the over ride to get it out of park.. Anyway, I did not have to change the whole shifter unit, somewhere along the way there was a BTSI open circuit, that needed to be changed, still enough money, but cheaper then the $540. shifter unit and then cost of labour, all in all, about $800. for both things to get fixed, shifter and lights,
    not impressed.
    See, cuz I still have to get my oil leak fixed and now, today, my heater fan decided it only wants to work on level 5... So either I have heat full blast or not at all.
    Yes, The Great Grand Prix.
  • It's a flaw in the system from my point of view. I have had 3 other GM vehicles with climate control systems and they all had the ability to turn the A/C off. Why doesnt this one? Somebody screwed up when they designed this, but it won't get changed so we have to deal with it.

    Mike :)
  • evandroevandro Posts: 1,108
    I had a Stratus with manual AC and the compressor would always come on when set to defrost too.

    Did your previous 3 GM cars have auto or manual AC?
  • etcbetcb Posts: 42
    Somebody screwed up when they designed this, but it won't get changed so we have to deal with it.

    I agree. it's stupid to have the AC running when it's cold outside, just to defog the windshield. The AC should auto disengage if temp is below 39. The car has a outside tempature sensor, so this could have been easily done. GM,, back to the drawing board. Otherwise, the car is reliable, has plenty of room , and fun to drive! :)
  • Did your previous 3 GM cars have auto or manual AC?

    The 3 previous cars were all auto climate control systems. Two GMC's and one Chevrolet.

    Mike :)
  • agree. it's stupid to have the AC running when it's cold outside, just to defog the windshield. The AC should auto disengage if temp is below 39. The car has a outside tempature sensor, so this could have been easily done. GM,, back to the drawing board. Otherwise, the car is reliable, has plenty of room , and fun to drive! :)

    I am not really sure that the compressor is actually running or if the a/c light is just on. When the temps get below 40 degrees, I think the compressors normally shut off.

    And as far as the car knowing the windshield needs defogging, I think the car is clueless. I have had it raining outside and the car does not know to switch it defrost mode. If I waited on the car to go to defrost mode, I would still be waiting. This was the same on the other GM vehicles I had with auto climate control. The only was you got the air output to the windshield was to press the defroster button. From there, ALL cars with a/c switch on the compressor when you turn on the defroster to help remove humidity.

    I just hope that is the biggest problem I come across while I own the GXP.

    My biggest fear is a blow out with no spare. Although I can rationalize that by thinking in over 30 years of driving I have yet to have a blow out and only remember one time having to change a flat tire.

    Mike :)
  • Sorry for the late reply. When a heater blower doesn't want to work on all settings, its probably the resistor pack for the blower motor. If your mechanically inclined you can change it out yourself. You can buy an aftermarket at a autoparts store. It may not look like the unit being replaced. Remove the plastic cover under the passenger side of the dash. The resistor pack is the electrical connection next to the firewall. Disconnect the the plug and take out two hex head screws. The resistor pack will fall out in your hand, hopefully. Put the new one in and retrace your steps. When I replaced mine, it only ran me about $25.00 and a half an hour of my time. If the blower motor quits, thats an ouchy. That cost me $91.00. Easier to change than the resistor pack though. Good luck to anyone trying it out. My 99 Grand Am is and has tried most electrical and electronic glitches recently. When it wouldn't start recently, it ended up being three fuses blowing all at the same time. They were replaced and its back to running fine for now.
  • porter2porter2 Posts: 2
    Hi everybody, I have the same heater problem with my 2002 Grand Piece, and through this awesome forum I found out that its the resistor pack for the blower motor. I just bought one tonight at the local auto shop for $29.99 and it looks pretty simple to change. The blower motor is located under a plastic cover on the passenger side under the dashboard. My resistor pack is manufactured by WELLS and the part # is DR783. I will let you know how i make out... Good luck with your Grand
  • How did your heater problem turn out? On my 2001 Grand Prix, my blower motor would only run on high speed. It would not shut off even after shutting the car off and removing the key. The only way I got it to shut off was to pull the fuse for HI, and now all speeds work except HI. I was wondering if that was what your problem was before you changed the resistor? Or maybe you didn't have any speeds at all? Please let me know what your symptoms were and what you did for a fix.
  • cdamechcdamech Posts: 31
    It's the Blower Resistors. It needs to be replaced. it is located under the front dash on the middle/passenger side. You need to unscrew the connector and then take out
    the board that has the resistors. It costs $60 to $90 at autoparts store.
  • Hi Kym, I have a 2004 GP GT and I am experienceing the sm problem, however, I do not have a sunroof, but I have been getting the runn around with the dealership I bought my car from. I bought it used and loved until the leaking started :cry: . As a matter of fact I have an appointment in the morning to take my car in for service to attempt to try and fix this problem. Thanks for the phone number, I can not wait to call tomorrow to complain.
  • sahoward1sahoward1 Posts: 19
    I've had my 2006 Grand Prix a month and have decided I cannot live with this air conditioner coming on all the time. It's totally ridiculous. My salesman said it could be re-programmed, but the service dept said "No, it can't." I emailed and called the Pontiac Customer Assistance Center---no help. They're giving me lip service about it de-humidifying the windshield. If that were so, it should only come on in defrost mode (I could live with that), but it comes on in every mode. I want to control my heating/air conditioning system. It should default to where I left it. I'm thinking of installing a kill switch, but am afraid of of voiding my warranty. Please help. I love this car, my third pontiac, but this air conditioner thing is spoiling my new car experience.
  • rmozolrmozol Posts: 124
    It's funny, but I've been more concious of this because of the posts. Yesterday, my AC stayed OFF after a restart; twice in fact. It was set on 61 degrees, in the dash vent position, and fan on about half. The outdoor temp was about 55 degrees too. The car was stopped about 2 - 3 minutes too. I thought that it happened once before, but I wasn't sure since I wasn't keying on it. This time, I KNOW it stayed off though. I'll keep looking for more oddities.
  • sahoward1sahoward1 Posts: 19
    The A/C does stay off sometimes... if you start the car right up again after shutting it off... like you said. But this is nonsense. I can't believe this A/C was intentionally programmed to come on at 40 degrees. I have to find a solution; it's making me crazy. I'm sure this is a screw up--I've never heard of a car's A/C coming on every time. And I've had automatic climate control on two previous cars. Has anyone found a solution? I'm desperate.
  • sahoward1sahoward1 Posts: 19
    The A/C comes on 95% of the time, even in manual mode. Has anyone figured out a fix for this? I think the A/C should default to wherever the driver left it. This is making me totally crazy. It's much worse than the pinging when you shut it off, or the hissing coming from the radio/fan. I'd be grateful for suggestions.
  • rmozolrmozol Posts: 124
    Yeah, it is annoying! My procedure to leave is start car up, turn off DRLs, grab gear shift, push AC button (off), put in reverse, and drive off. They say responses become automatic after a few thousand repetitions!
  • sahoward1sahoward1 Posts: 19
    That should not be necessary. Computers are supposed to help the driver, not hinder. Why should that A/C compressor come on when it's 41 degrees? The guy at GM actually told me that would help the compressor last longer, because it would get lubricated every time it came on. How lubed can it get if the driver shuts it right off? Anyway, I read these posts going back a year, and apparently the AC never came on with the remote start. So the fix was to have it always come on? And I'm not even talking about the remote start, it happens with any start up. This is not right.... and I have not finished with GM yet. I've had three Impalas, a Bonneville and two Grand Prix. I bought one son a Grand Am and the other a Cavalier. But I'm furious about this.... I asked for a default to off, a default to where I left it, or a reprogram to come on at 80 degrees--all reasonable requests. GM acts like they never heard of this. I had to leave my car at the dealer for a whole day for them to tell me this was normal. Well, if it's so normal, couldn't they have told me that on the phone? I'm thinking of pulling out the AC fuse from October thru April. I live in New England. There must be a solution to this.
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