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Pontiac Bonneville Heating/Cooling Problems



  • Thank you VERY much! The link you provided gave me the clue to look through the inspection hole behind the glove box...


    The actuator rod is (barely) visable through the left (drivers side) hole which I circled in red.

    Here's a close up, although, I couldn't get my camera to focus on the rod itself.


    It was a simple matter to take some bailing wire, loop it around the actuator rod end, pull it towards the passenger side of the glove box (which opens the door for heat evidently), and tie it off. That will keep my wife (not ot mention my marriage) warm for the winter. :)

    To actually get at the actuator motor looks to be a real challenge and if my 200k Pontiac makes it through the winter at all, MAYBE I'll attempt to replace it come spring.

    Thanks again!
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,046
    I took the slipping actuator off my leSabre and used superglue between the white nylon gear and the gray plastic axle to hold it. I figured if it didn't hold, I just remove it again and replace. But the car has nearly 200,000 miles and I never know how long I'll keep it.
  • This is great timing! My 96 Bonneville SE has 135K & has the same post battery replacement/ACC issue as mentioned by "tgonya". I have just replaced the thermostat & heater issues not fixed (wish I had been on here 1st). The dealer diagnosed it as the A/C Programmer & $700 for the part just today. Not going there! Will try the Air Mix Actuator recommended by "imidazol97" & pictured by "tgonya". Thanks a bunch guys! Will let you know the outcome.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,046
    If you do anything that disrupts power in your car, use the key ON and turn the HVAC controls to OFF and let the unit shut down. Many people think that when the unit is left mid position and then power is restored it breaks the gear or forces a slipping as it does the startup movements to max heat and then max cool to locate the positions for the computer. This may only apply to the auto control unit, but I'd shut down the manual unit too to protect its actuator.

    I'm really glad that something I've learned from the past adventures with my H-body and reading other's posts has helped someone here. I appreciate it when someone comes back and says it did help.
  • Hi, I've owned this car since new. A couple of years ago the blower started working intermittently. I would set it and it would come on when it wanted to. I have noticed that it would seem to speed up as the engine RPMs increased. That makes me think vacuum leak. I just put up with it, but now it has it has pretty much ceased to function, though it did come on last weeks for a couple of seconds. I had frost on the windshield so I had it in the defrost mode. Eventually, the warm air rose on it's own and partially cleared the windshield. I don't think I have a heat issue, just getting the fan to work. Does anyone have any ideas?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,046
    What kind of HVAC system do you have: manual or automatic with digital readout.

    If it's the digital readout, you have a blower speed module that can fail in strange ways. Or it could just be the blower motor is failing. The motor is about 5 screws on the firewall on the back of the engine compartment.
    The blower speed control module is above the motor sitting down into the air path for cooling.

    The Relay Center above that is held in by two screws and can be raised if they're removed for easier access to the two screws hold the BCM in place.

    If you ahve the manual system it's most likely the blower motor. Intead of the module, the manual system has a resistor pack for changing speeds.

    The motor can be tested in place with a fused lead from the battery to the purple wire. You have to also provide a ground for the black wire.
  • I have the auto digital as pictured in Post #221. So, if the motor doesn't work with the test lead, I'm looking at replacing the blower speed control module? Are these parts available at most auto supply stores?
    Thank you very much for your help. I'm going to get on this this afternoon.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,046
    > the motor doesn't work with the test lead

    No. If the test of the motor using a fused power wire from the positive battery terminal to the purple wire and a ground to the black wire makes the motor run just fine--at full speed--, then you _probably_ have a blower control module problem.

    They are available from, and various box stores, along with the recycling yards. Depends on how much you're willing to fuss over it from recycling, such as the pick-and-pull yards.
  • 1howard1howard Posts: 1
    edited February 2013
    I am amazed how long this thread has been going. This has to be a design weakness in the Pontiac. I had the same problem but it could go either way, hot in the summer, cold in the winter. I didn't want to work on the problem by having the dealer throw my money at it. The fix I show has been in place for at least four years (just checked, can't believe it was May 2005) and almost always works. I concentrated on the nylon pivot for the control arm and use that to move it back and forth from hot to cold. When it is working changing the temp from hot to cold you can see the arm moving if the glove box door is open.

    I upgraded the arm to metal from wood several years ago. There are times it jams to the right (cold) and I don't want to force it. Usually turning the climate control off completely will allow me to move the arm. Fortunately the car is narrow enough to reach the arm while driving w/o dropping my cell phone, spilling my coffee or losing my donut. :-)

    Here are some pictures and description that may help you understand what I did, but not necessarily motivate you to do it.
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