Pontiac Grand Prix Climate Control/AC



  • brybrybrybry Member Posts: 25
    Hi Joe, I had the same problem with no heat on my 2000 grand prix. I had a low temp reading on my gauge on the dash. I replaced the thermostat and coolant sensor but still no heat and still a low temperature reading on the guage. Turns out the most expensive 'no fail' thermostat was faulty. Went back and bought the cheapest one and is working fine now with lots of heat. The temp guage was probably fine too. Hope this helps.
  • sailers2sailers2 Member Posts: 3
    I have a 2000 Grand Prix, and it goes crazy once in a while... I can be driving in 90 degree weather, and everything is working fine, and all of a sudden it thinks that the temp. has dropped to 34 or lower outside, and start putting out heat.... sometimes it takes an hour or so to come back up so the air will start working again... How do You fix this?
  • waynneo1waynneo1 Member Posts: 1
    I bought this Grand PRix in June, and now that it is colder, the engine temp only rises as high as 175 degrees. I replaced the thermostat, and I noticed the electric fans kick in right away so I will need to replace the thermostat controlling them as well. I have disconnected the fans to try and get the engine temp to come up but to no avail. Even idling in town traffic it doesn't go over 190 with the fans off. I live in WI and we have had some below zero weather already and on those days the temp gauge doesn't come off 160 which gives me very little heat. Am I overlooking something else that could be allowing the water to flow around the theromostat? I've never heard of such a thing, but anything is possible. Any help??
  • brybrybrybry Member Posts: 25
    My 91 olds ninety eight had the same problem. I replaced the exterior thermometer sensor. It was under the hood near the left headlight on this model if I recall. Once replaced all was fine.
  • sailers2sailers2 Member Posts: 3
    Thank You, now all I have to do is find where it is on a 2000 Grand Prix??? Anybody know?
  • yakkymomyakkymom Member Posts: 1
    We have a 2003 Grand Prix that has about 100,000 miles on it. We are experiencing something weird and hopefully someone can shed some light on it! The heat only works when we are driving on the freeway (70 mph). As soon as we get off the freeway, it just blows cold air. Does anyone know what this could possibly be? We are going to replace the thermostat (if we can find it) and see if that helps. Help!!
  • sailers2sailers2 Member Posts: 3
    I am no expert, but it kind of sounds like You good be low on coolant....only when the rpm.s are up.. the water circulates better and reaches the heater.??? You could be lucky and that is the only problem......Sailer2
  • jmattersjmatters Member Posts: 1
    Hi, I read alot of comments in here, but with my 02 grand prix my heater worked one day and the next it will only work on 5, same with the a/c. My headlights work just fine and so does my rear window defroster. Do you think it's the resister?
  • treacottontreacotton Member Posts: 2
    Hey Storm21935,

    I have a 2001 GTP and I have been having this problem like you had. Blower won't work unless on 5 and sometimes it takes 10-15 secs to come on.. hear a clicking under steering column, AUTO headlights have to be turned on manually at night, and I have also been having problems with my mileage computer screen going out related to this. Have you figured out the root of the problem? If so please let me know what I can do to get this fixed otherwise I am going to probably get charged over $100 for repairs.
  • rgh1016rgh1016 Member Posts: 5
    Vehicle has a dual-control a/c unit.

    Problem: If both temp controls are set to the same temp in dual mode, or if a temp is set at the drivers control in single-control mode, the temperature of the air exiting from the drivers vents is substantially warmer than that exiting from the passenger vents.

    Actions taken: Drivers blend door motor and the exterior temperature sensor have both been replaced with no improvement noted. The driver side blend door can be manually moved through its full travel with no resistance noted. Running the diagnostics program through the climate control panel shows no current codes.

    Question: Any suggestions on how to resolve this problem will be greatly appreciated.
  • nick8180nick8180 Member Posts: 2
    I'm having similar problems anyone reply yet?
  • rgh1016rgh1016 Member Posts: 5
    Thus far I have received no corrective-action replies to my problem report. I am sure this problem has been seen and corrected by someone before so maybe we will get a solution soon.

  • rgh1016rgh1016 Member Posts: 5
    Here's what I have learned in the process of trying to isolate this problem:

    1. No OBD current codes are indicated when accessing the diagnostics
    through the climate control panel. A history code of 105 shows because I
    removed and replaced the driver-side blend door motor.

    2. With the driver-side blend door motor removed I could detect no
    binding when physically moving the blend door from full-heat to full-cold
    position. However, when the blend door was physically moved to the full
    cold position the temperature out of the driver-side vents was 40 degrees (the same as out of the passenger side) in single mode operation.

    3. Changing the driver-side temperature control from full heat to full
    cold positions appears to cause the driver-side blend door motor to move
    through its full travel (that is, from the full heat index marking on the
    motor to the full cold index marking). However, the driver-side outlet
    temperature is approximately 15 degrees warmer than the passenger outlet
    temperature when the temp control is in the max cold position.

    4. Replacing the driver-side blend door motor and the exterior temp
    sensor did not correct the problem.

    It appears to me that for some reason the driver-side blend door is not
    being moved to the full cold position when the motor is installed and the
    temp control is set at max cold even though the motor appears to move to the
    full-close index mark.

    Is it possible the a/c & heater controller is commanding the blend-door
    motor to a position just off the full cold position even though the motor
    appears to be at the index mark?

    Because of item 2. above, I am convinced the blend-door motor is not moving
    the door to the full cold position even though the shaft position index on
    the motor appears to indicate otherwise.

    Is it possible to adjust the blend door shaft positionslightly so the motor
    will definitely move the door to the full cold position when the temp
    control is set to max cold?

  • nick8180nick8180 Member Posts: 2
    Problem solved ignition switch
  • shawnp04shawnp04 Member Posts: 1
    I have a 2004 Pontiac Grand Prix and i have noticed that when i press the recirculation button the light comes on but it doesn't block out any outside air. What can i do to fix this problem?
  • lfdtdlfdtd Member Posts: 1
    You might check the passenger compartment air filter that is right above the blower motor. My heater quit blowing altogether and I checked the air filter and it was wet and stopped up. I changed it and it works better than ever. All vehicles from the 90's up have an air filter coming from the blower.
  • keith2186keith2186 Member Posts: 1
    I have had the same problem auto care center said ac/heater control unit was bad they were wrong. If you unhook your blend motor from the door unit but leave wired turn your car on and turn your temp. down you should see the motor move if it is not lined up with the marker line on the motor take apart blend motor case and align gear with mark you may have to do this two or three times to get it right there is some type of travel sensor in the unit . once you are satisfied with this with your hand turn the actuator for the door to insure in right position (cold air coming out) the motor should slide back on with ease if everything is in the right spot . Let me know if this works for you
  • streetchariotstreetchariot Member Posts: 2
  • streetchariotstreetchariot Member Posts: 2
    What steps are needed to replace the SE climate control with the digital/dual climate control?
  • jakedavejakedave Member Posts: 2
  • jakedavejakedave Member Posts: 2
    I have a problem with my climate control. The external thermometer reads the wrong temperature, which makes the climate control not work either. For instance, yesterday the actual temp was around 70 degrees, and my thermometer read -6, so it will not turn the a/c on or anything, and it happens once in a while the opposite way too (like it will be zero outside and the temp will read like 90, so it wont heat properly). I replaced the ambient air temp sensor and it did nothing for the problem..Does anyone know what the problem would be? Thanks

    Another small problem I have is that my automatic lights do not work all the time.. They wont work for like a month or so, then all of a sudden, one day they will work, and will continue to work for a few weeks or months, then out of the blue they will stop working agian...i tried replacing the headlight switch assembly just because it was cheap and i figured i didnt have anything to lose, but it didnt solve anything...anyone know what that one would be?
  • mose1mose1 Member Posts: 1
    Have you ever been able to resolve this problem? I have the exact same problem with my 2003 Grand Prix>
  • slemiskaslemiska Member Posts: 2
    My heater/ac fan stopped blowing. when the AC is on I get cold air just no blower. All the controls to switch where the air is coming out and what mode it's in seem to work. Where do I begin to figure this out.
  • suthrngntlmansuthrngntlman Member Posts: 1

    Has anyone ever replied to you with a solution to this problem??

    THANX!! SuthrnGntlman
  • slemiskaslemiska Member Posts: 2
  • bearmdebearmde Member Posts: 2
    I just finished replacing the heat resistor module on my 1999 Pontiac Grand Prix that everyone states is needed to get fan speed 1-4 working. My car will work on five only. Well it still only works on five only. I tested the switch by using a jump wire from hot to make sure 1-4 are working and the switch is good because it still does not work. Now I have been told that it is possibly a blower motor control module. This module is on drivers side, by left leg, near outer panel of door. It is also a very expensive part. It seems the switch relays are small, and they go through this module to a set of stronger relays then on to the heat resister module. Has anyone ever heard of this going bad and are there any after market ones that are available.
    The next issue, is still with the blower. With the lights set to come on automatically like most cars are today, if the switch is off, the lights will come on. The second that you turn the blower switch to 1-4 the lights will go off, and only come back on by going to off or 5. Somehow this is all tied together. Any ideas from the experts on this panel. Thanks.
  • billyshrbillyshr Member Posts: 1
    I have a problem. no heat in my 2000 grand prix i changed the thermostat then noticed the knob and switch that changes the temp of heat/air was broken . does anyone know how hard a fix especially pulling the dash. I noticed in other forum on switching radio that when you pull down the dash there is still more dash to take off to get to switches. any help would be appreciated alot . also what other issues could i have if that is not the problem thanks bilyshr
  • dmen921dmen921 Member Posts: 2
    Hey there jakedave,

    Just wondering if you ever found a resolution to this problem. I'm having the same problem with my 2000 GT. Thanks

  • dmen921dmen921 Member Posts: 2
    I have a problem with my climate control. The external thermometer reads the wrong temperature, which makes the climate control not work either. For instance, yesterday the actual temp was around 70 degrees, and my thermometer read -6, so it will not turn the a/c on or anything, and it happens once in a while the opposite way too (like it will be zero outside and the temp will read like 90, so it wont heat properly). Any ideas. Thanks guys
  • publicmsupublicmsu Member Posts: 1
    2000 Grand Prix with the cj2 (automatic) climate control system. I was receiving the blinking man on my HVAC head, so I checked the diagnostics through the cj2 diagnostic mode. I was receiving a current code of 05 which indicates driver side fault on the blend actuator. I replaced the part and while doing so, plugged it in just to see if it worked, without having it hooked up to the actual blend door. The motor never moved, no matter which temperature was selected on the driver's side, but the current code went to history (good). Now I am trying to decide what my next point of attack is. I do not have any current codes (105 is there, but history), and my driver's side blend door does not move (cannot hear it, but can hear the passenger when adjusting the temp). I also noticed that my driver side backlight that illuminates the dial for driver's temp is no longer illuminated. I assumed this was just a burned out bulb and the system was still fine. Now I'm starting to wonder if this is another diagnostic that's trying to tell me there's bigger problems with the driver's side HVAC control? Has anyone encountered this loss of backlight?

    As another side note, I'm wondering if it's worthwhile replacing the interior temperature sensor. I've already replaced the exterior ambient sensor, as that was way off; that is working fine now. Just trying to get my HVAC system back into original working order.

  • jfisshjfissh Member Posts: 5
    I am having the same problem. Did you ever get it fixed?
  • rgh1016rgh1016 Member Posts: 5
    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 Member 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 Member 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 Member 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.
    [email protected]
  • jfisshjfissh Member 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 Member Posts: 1
    I have a similar problem with my 1997 Grand Prix. Did you get an answer to your question?
  • jfisshjfissh Member Posts: 5
    Nope, Not yet. I'll post a solution here if I ever find one. Please do the same! :)
  • msproutmsprout Member 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.
  • jmolejmole Member Posts: 3
    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.

    [email protected]
  • jmolejmole Member Posts: 3
    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.


    [email protected]
  • swamp_gatorswamp_gator Member Posts: 3
    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.
  • gmfan007gmfan007 Member Posts: 77
    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.
  • rgh1016rgh1016 Member Posts: 5
    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.
  • grandprixfan2grandprixfan2 Member Posts: 1
    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.


  • gmfan007gmfan007 Member Posts: 77
    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.
  • 2004gtpcompg2004gtpcompg Member Posts: 1
    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 Member 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 http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dautomotive&field-keywo- 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.

  • vgolfmastervgolfmaster Member Posts: 4
    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.
  • swamp_gatorswamp_gator Member Posts: 3
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