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Pontiac Grand Prix Climate Control/AC



  • brybrybrybry 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.
  • 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?
  • 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 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.
  • Thank You, now all I have to do is find where it is on a 2000 Grand Prix??? Anybody know?
  • 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!!
  • 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
  • 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?
  • 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.
  • 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.
  • I'm having similar problems anyone reply yet?
  • 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.

  • 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 Posts: 2
    Problem solved ignition switch
  • shawnp04shawnp04 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 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.
  • 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
  • What steps are needed to replace the SE climate control with the digital/dual climate control?
  • jakedavejakedave Posts: 2
  • jakedavejakedave 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 Posts: 1
    Have you ever been able to resolve this problem? I have the exact same problem with my 2003 Grand Prix>
  • slemiskaslemiska 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.
  • Hello!

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

    THANX!! SuthrnGntlman
  • slemiskaslemiska 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.
  • 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
  • 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

  • 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
  • 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.

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