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Pontiac Grand Prix Climate Control/AC



  • I am having the same problem. Did you ever get it fixed?
  • If you are referring to the problem of unbalanced cooling output between the driver and passenger outlets, I found debris in the metering valve that apparently came from the compressor when it failed. After changing the metering valve, the difference in temperature between the driver and passenger outlets was about 6 degrees when the controls were set to 60 degrees and that's probably within spec. That's much better than the 20 degree difference I had been getting. The amount of debris in the metering valve certainly didn't appear to be enough to cause this much of a cooling difference so it must be very sensitive to obstruction.

  • gp76gp76 Posts: 1
    I have a 05 Grand Prix with two problems,The first is it wont start on the first crank every time unless I push on the gas.The secound is the A/C kicks on when it does start every time no matter what the temp is outside, even when its not on auto.I have cleaned the ground to the body and the battery termals and I have no codes flashing anybody got any ideas?After reading the post on here I see the A/C is a problem that may not have a fix that stinks.
  • xwiloxxwilox Posts: 1
    Hey Wayne I have the same problem only 3 years later 2009. Did you ever figure the solution to yours. If you did please post the solution. Thanks.
  • kejgibkejgib Posts: 1
    Hi there,
    My blower worked on the high speed also for a while, now it is dead, and it is cold in Boston. What was your solution for the problem? Thanks in advance.
  • jfisshjfissh Posts: 5
    I had the same problem, I replaced the blower motor resistor and it did not solve anything. Actually the resistor that was in there was the new model, so I ordered a part for nothing... I still have it, would you like to buy it from me?

    I also had a car starter installed (a viper) and I thought that it was the problem because everything would work when I started the car with the remote, until I depressed the brake (which disengaged the remote starter) and then everything would die. So, I had it removed, and it still didn't fix the problem. So I scheduled an appointment with my local GM dealer to have it looked at.... Guess what happened.... The DAY I took it in, everything started to work properly.... just my luck. They kept it for two days trying to get it to act up, but nothing. After an $80 bill, no remote starter, and a big headache I am left with a working blower and HUD, but no guarantees that this spring, or when I get the car starter installed again that it will work properly still.

    So anyway, I am very curious if you have a remote starter installed? That still may be the problem. Please let me know.
  • jmartosjmartos Posts: 1
    I have a similar problem with my 1997 Grand Prix. Did you get an answer to your question?
  • jfisshjfissh Posts: 5
    Nope, Not yet. I'll post a solution here if I ever find one. Please do the same! :)
  • msproutmsprout Posts: 1
    Most GM Vehicles have plastic vacuum lines which over time they tend to crack and break. My son has a 1994 Camaro w/3.4 engine. We had a smoke test done on it by a mechanic which indicated a vacuum leak on one located behind and underneath the front passenger side bumper. So we replaced it and he now has his ac when he accelerates and it does not go to the floor anymore. It remains out the vents like its suppose to. So my recommendation to you is if see where you can have a smoke test done but not at a dealer because they will charge you a arm and a leg if you know what I mean. A smoke test will show any and all leaks throughout your vacuum lines. Also this will help you replace only the one you need to. I'm sure and I also was told by 3 different mechanics that you have a vacuum leak somewhere.
  • Hi Folks,

    I've read all 197 post here and found a lot of good information, but haven't yet seen a post for my particularly problem.

    I have a 2004 Grand Prix GT with only 40 K miles. About 9 mo ago I started having problems with the CCS fan not coming on, but no problems with AC or heating when it did blow. Most of the time it worked and when it didn't I found that just opening and closing the door would cause it to start working again (jarring a connection I presumed). Also, my wife who could reach under the console found that moving the wires leading into the console would sometimes work which I didn't understand since they don't lead to the CCS. As it worked most of the time, I (we) put up with it, but over time the problem kept getting more and more frequent.

    Finally, last month the fan got to where it would not come on at all. So, figuring maybe a loose wire I took all panels off, but didn't find any loose wires (at least going to the motor and what I guess is a relay or resistor of some sort behind the motor and up against the firewall. I also check all the fuses under the hood and dash side panel and all were ok. So while exploring online we continued to drive the car.

    Now all of a sudden it is working again and has been ok for at least 2 day now, so I can figure out what the H is going on, but obviously it must have something to do with the fan.

    I should mention that the 2004 has a variable fan speed dial and not the 5 settings that are mentioned for other earlier model Grand Prixs, but I can count 13 click on the dial as I go from low to the highest setting. It's just that there are no numbers on the dial itself.

    Before I go taking out the fan and replacing the resistor pack, I am hoping that someone can give me some suggestions as to what might be causing my problem that I could easily check out.

    In addition to answering on this forum page, please forward my home address at jmole@charter, so that I not miss it if I don't get back to this page.

    Thanks very much in advance.

  • Also, forgot to ask if anyone knows whether an OBD scanner will identify a faulty component on the CCS as I've read that beginning in 2005 the Grand Prix's computer incorporates CAN information from the CCS. I am uncertain whether some or all of the 2004 models have this feature, but my 2004 factory repair manual mentions hooking up a scanner to identify the problem, it just doesn't say which scanner.


  • Hello,
    My 2000 Grand Prix blows air out through upper, lower, and defrost vents when I have it set for full face. It isn't blowing as cold as usual either but I do hear the compressor turning on so I know the AC is actually working. I have changed out my climate controller and I still have the same problem. Is there a way to reset the controller or do you think the problem is elsewhere?? It used to switch from full face to all vents for just a little while and then it would switch back but now it won't switch to full face at all and it gets hot inside being from Florida. Any help would be greatly appreciated. Also, if I push the defrost button it does switch to full defrost and then when I switch back to full face it goes back to all three vents. It is not a controller issue since I have replaced that.
  • I'm having the exact same problem with my '98 GT and suspect the passenger actuator. Wondering where it is located and if it was difficult to replace. Thanks for the help.
  • On my 2000 GT with a similiar problem (warm air out of left side and cold air out of right) the problem was not the actuators; they worked just fine. It turned out to be the metering valve. This device was not changed when the compressor was replaced and it apparently was partially clogged.

    As for the actuators, they are located on each side of the air routing box. They have an index mark on them so you can see them rotating as you adjust the temperature control. If they move through the entire range as you rotate the temperature control, they are working correctly.
  • This is unrelated need to know how you removed your a/c controller. I have everything removed except the middle piece. It looks like it doesn't come out. The left and right is already out. I'm trying to replace some burnt out lights by resaudering and need to get to the back of the circuit board.


  • Thanks for your help. Turns out, both driver & passenger actuators were stuck. Both large plastic gears inside were cracked preventing proper rotation by motors. All is well now. BTW: Passenger side was easy access, but driver side was a bear.
  • john
    Have you found out the problem? I'm having the same issue with my 2004 gtp some times you shut the hood and it turns on.
  • jmolejmole Posts: 3
    Yes I did. It turns out it was the motor fan resistor that I mentioned in my original post.

    I found this out by tapping lightly on the resistor with the fan set to on, but when the fan was not working. After a few taps the fan will restart, but after a few days I have the problem again.

    So, I took the resistor off (there are two plastic rivets holding it on which can be snapped by twisting the resistor). The resistor can be replaced with metal screws and there are two holes in the body of the resistor for this purpose.

    My local auto parts dealer wanted $110 for the resistor so I decided to take it apart and see if the internals were burnt. Everything looked ok, but I found that there was a thermal compound (about consistency of modeling clay) on top of a small chip and which breaks apart when the two half of the casing are taken apart.

    Thinking this might be analogous to the thermal grease used to ensure good heat transfer from the CPU to the cooling fins and fan, I repacked the material to ensure good contact with the chip and reinstalled it. This seemed to work ok most of the time, but I still have the problem intermittently.

    By now, I'm getting tired of having to mess around with it and will be ordering a new resistor which I found at Autozone for $96.

    My old resistor looks exactly like this one.

    I found other sites that list the RU359 as a replacement for my grand prix for around $62, but it looks different.

    See rds=Standard+Motor+Products+RU359+Blower+Motor+Resistor&x=20&y=19

    If you are adventurous and want to save a few bucks you could try it as a replacement, but I think I'm going to follow my mechanics advice and reinstall one that looks identical to the original.

    Hope all this helps.

  • Hi all,

    We have a 1997 Grand Prix (3.8l) that has an issue where the control for directing air flow does not change the actual air flow direction. It is stuck split between the defroster and floor, so it is tolerable, but I'd sure like to get it fixed for my wife. Does anyone know if these controls are vacuum operated and if that is where I should be looking, or if I am looking at replacing the entire control panel for this?

    The fan control works fine, the temperature adjustment works fine, and the push buttons for A/C and rear defrost work fine, it is ONLY the adjustment for air flow that is not working.

    Thanks in advance,

    Mark in chilly Wisconsin.
  • Yes they are vacuum controlled. If you pull out the glove box on the passenger side you will see a control module with vacuum lines going to it. You can check the vacuum at each individual line to see which vacuum module is bad. They are all color coded so you will be able to trace it easily. The vacuum modules are replaceable without pulling the dash. Hope this helps.

    Marc in Sunny FLA
  • It has to be a leak in the vacuum line that controls the flaps inside the dash that block the ducts except for the one you set the control knob to. It then closes off all ducts and leaves the selected vents open. It's all run by vacuum. I had this same problem with my 1998 Dodge Ram pickup. You should research where the vacuum line is located. I think it runs from the intake manifold and end up under the battery where it attaches to a fitting. Usually the battery will end up corroding the line over time. Thats more than likely the problem.
  • I have a 1997 Grand Prix GT 3.8L not supercharged. The guy we bought the car from said that the heater blower only works on level "5". I have read a bunch of these forums and nobody has really figured it out. I have heard two things that sound most likely to be my problem. One is the fan ignition switch? Need to research and find out what that is. The second thing is the resistor. Not really sure here. Also the rear window defrost won't turn on and stay on. I have had it stay on for maybe ten seconds and then the light turns off. I don't know if that could be related to the blower problem or not. My thoughts are that someone may have used something they shouldn't have and sliced through one of the delicate wires. I haven't got up close and looked at the rear window yet. My biggest concern is getting the blower motor to work on all five speeds. Anyone have anything?
  • The level five heat is the blower motor resistor I'm positive of that. I dont have a clue as to the rear defroster and the resistor can be purchased at any auto parts store. this video is of a sunfire but the process is the same . Good luck with the defrost

    (personal experience replacing 2 resistor based on three years automotive schooling)
  • joeg1joeg1 Posts: 18
    My 98 Grand Prix GTP's CJ2 Digital Heater - A/C Control is putting out only 0.01 volts at C11, "Blower Speed Control Signal," when the CJ2 connector is back probed and the defroster is set to high. I have performed the diagnostics, "Blower Motor Inoperative at Any Speed," several times always reaching the final step, # 29, which is to replace the Heater - A/C Control.

    I replaced Heater - A/C Control with two different units - both represented as good - and still only 0.01 volts at C11 where the factory specification is 0.5 to 7.0 volts. All three Heater - A/C control units function correctly in all other respects and in the diagnostic mode position 00 is 00.

    Any ideas? This problem has bedeviled me for months.

    Many thanks,
  • mcsherrysmcsherrys Posts: 1
    I had the same problem with my 97 GTP. Turns out that the hard plastic vacuum line located under the windshield fluid reservoir and to the rear of the battery deteriorated and vacuum was lost. I reconnected it with a new vacuum hose and now it works great!
  • I am having the opposite problem from everyone here. My AC is registering -9 to -16 degrees outside when it is 107 degrees, so the AC doesn't come on. It only stops working at the hottest part of the day. It works in the morning and at night when I don't need it, of course:) Does anyone have any idea what this could be?? I have a 1999 pontiac grand prix.
  • In case anyone else has this problem. It was the exterior temperature sensor at the front passenger side of the car. By the radiator almost on the plastic of the car. It was a $9 part and easy to fix:)
  • Hello, I have the same problem. I have a 1999 Grand Prix..It just started doing this after I changed the battery and alternator. We have checked all the fuses and finally ended up changing the resister..and still the blower will only work on 5 and it is affecting the running lights..if the blower is on i have no lights. We have run out of ideas. I havent taken it to a garage my backyard mechanic has spent hours checking wires and fuses. Has anyone else had any similar problems or solutions??????
  • I have the same problem with the daytime lights and the rear defogger. I am worried that the resistor is not the problem. I have had my mechanic look at it but he could not give me a reasonable answer other than replace the entire HVAC. Has anyone figured out what is causing this?
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