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Pontiac Bonneville Heating/Cooling Problems



  • wesleynkywesleynky Posts: 1
    I have a 92 Bonneville(yes it still runs). The blower fan for the AC/Heater will not work at all at any speed. It just suddenly quit and has not come back on since. I looked to see if the fuse had blown but it has not. Any ideas on what to investigate next. It is hot in Ky this time of year. I can get enough flow if I am out on the highway from vent air running through the AC to stay some what cool.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,048
    You didn't say if you have automatic temperature control or the standard HVAC.

    If you have standard (C67) no digital readout, there are two relays that switch. If one is burned, the blower doesn't work on the lower speeds and if the other is burned the system doesn't have the highest blower speed.

    Since you don't say that it works on one speed or other, check the ground from the blower motor. AND first you should disconnect the blower motor plug from the resistor pack on top of the air channel (the relay center lifts up after loosening or removing one or two screws, and test the blower motor with a FUSED power line from the battery and a ground.

    Fuse 17 and fuse 11 in the driver's dash panel. Fuse #3 in the Fuse and Relay center on the firewall under the hood -- but that only powers the high blower speed.

    If blower works then check the connector for good ground connection.

    If you've got the dual, automatic temperature control with digital readout, then it may be your blower motor control module that replaces the resistor pack in the top of the air duct under the hood. Again if the blower motor checks okay with fused wire, then the control module may have died. I'm told they're available aftermarket at Advance Auto and others. Also might find compatible at junkyard.

    It may look like this found on with a price of $119

    Also on dual system Fuse 1 in fuse/relay center on passenger inside car under dash against A pillar area. Remove plastic panel above passenger's feet. On top of panel may be schematic and llist of relays and fuses in that forgotten panel.

    Also underhood firewall it's fuse 3. And on this unit it looks a blown fuse 3 there stops all speeds unlike the manual control system above.

    Note there are two fuse and relay centers I've mention: one is on the firewall under the hood and the other is by the passenger's right foot.

    This info is from a 1993 leSabre/ParkAvenue factory service manual. I may not be what's used for the Pontiac in 1992.
  • pfunk1410pfunk1410 Posts: 1
    ATTENTION EVERYONE: if your A/C blows cold but only comes out the defrost or foot vents but not the middle vents this is probably your solution:

    It worked on my 1998 Pontiac Bonneville and using the "Plan B" directions it cost $1.29 to repair, all I needed was about a foot of vacuum line from my local auto-parts store.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,048
    To test to see if you're getting vacuum to the inside components of the car you must have the motor running or just have shut it off. With it running get your head down on the hump and listen and watch for vanes to move. I put my fingers on the backside of the vacuum motors and felt for movement as the various buttons on the heater controls were pushed.

    I'm concerned you said you didn't get a lot of vacuum at the tank. How long had the motor been off. When I did it, I had turned the motor off a minute or two before and when I got down there I could hardly pull the line off because there was so much vacuum.

    Your next step if you don't get movement testing the various HVAC motors like in paragraph one is to go to the right side of the dash and follow the violet line up to where it's connected to the black line from the motor side of the firewall. Pull them apart (may be hard, they've been together a long time). See if there's vacuum on the black line when you put your moist fingetip on it!

    If there is vacuum and some of the other motors work, but the blue line one for the defrost/AC door doesn't, then most likely the connector at the programmer is sucking shut the little black nipple. You can bypass one, the blue one, or all with1/8 inch gas line chunks or aquarium line that fits tightly over the outside.

    This link tells one story which I had posted on Edmunds long ago.
    Repair link

    These pictures show the rubbery plastic connector after I cut the lines off. You can cut only the blue line inside and outside and bypass them.

    The connector comes out of the slot on the programmer box when the lid is snapped out using the black clips on one side.

    imageSee more Car Pictures at

    imageSee more Car Pictures at
  • sharp_ctsharp_ct Posts: 1
    :sick: My daughter has a '99 Bonne, manual heat controls. She says A.C. has been getting warmer over past week or so and has now stopped working altogether. I checked under the hood and the compressor is not kicking in when A.C. is turned on. More disturbing is that I also noticed that the main engine cooling fan is not kicking on either. I have checked all the fuses under the hood and the dash with a meter, and checked comp power lead to find it is not getting power to the clutch with A.C. on. Just coincidence that cooling fan failed at same time or is there some common circuit I should be looking at? Any thoughts or leads would be greatly appreciated. While she could live w/o the A.C., I'm afraid to let her drive it if the cooling fans are not coming on, even though it doesn't seem to be over heating. Thanks you in advance
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,048
    If you feel up to working with simple air conditioning equipment (as opposed to the full set of gauges), you might get a can that has freon in it from Walmart and get one of the gauges they have that can snap to different cans. Attach the can to the low side (it'll only fit that one) and see what pressure you get when you run the AC.

    I suspect you'll be below the minimum pressure to engage the switch to operate the system. Myself I would use the can and put in freon up to the correct color and see if you aren't getting some cooling. Then you can see if it goes down again or not.

    I had my 98 get not cool when the outside really got warm last summer. It had seemed okay earlier in the summer, but when the outside when up to 90 and above it was lacking. After 11 years I guess it seeped enough R134a that it was low. I put it back up to the proper level and I've had cooling since--including so far this summer. So I don't think I had a slow leak. You might check the condenser and tubing and look for oiliness as a sign of a leak which brings out some oil with it.

    The fans will come on through a separate circuit for coolant heating up. The no freon may be keeping them from coming on with the AC.
  • I have read all the forums now and have done everything you guys have suggested. Only problem is now you can not control what setting the air blows out of. It will only come out of the A/C vents which is fine until you shut the car off and turn it back on. Now it will blow hot air either out of the A/C vents or out of the defrost. If you unplug the main vaccuum line and plug it back in it may or may not change it back to A/C and coming out of the vents. any suggestions?
  • Also we did bypass the multi vaccuum line plug and reconnected all the lines with surgecial tubing by color code. Initially when car was started desired vents were blowing cold when engine was turned off and restarted, hot air was blowing from same vents. The blue vaccuum line was disconnected and then reconnnected changed the hot air to cold air blowing back through the vent. The same cycle was repeated several times, with same results. We could hear internally the door which directed hot and cold, actuating after each start up.
  • bonne03bonne03 Posts: 3
    I have an 03 Bonneville SLE with a strange quirk. It has the Dual Climate Control with Digital Readout. In the past month or so when I start the car it will light up and appear to be working however no air is coming out the vents. The settings can't be changed (changing to defrost vs. auto etc) .. after a period of time driving down the road (sometimes up to 20 minutes) then it will begin to function normally and then does work fine. I did replace the control unit itself but that hasn't fixed the problem. When it does work all settings can be changed, air blows as it should etc. it will work perfectly .. however the long delays are beyond a nusiance and I'm worried this winter about not having defrost (of course having a/c right now would be nice also)

    Has anyone else had this problem, any ideas how to fix?
  • I have a 2005 Bonneville. It isn't an SE or anything special. It has been running great until recently. Most of the time when I start the it the heater blows, but sometimes it doesn't. Sometimes when it doesn't start upon initiation, it will eventually come on, other times it just doesn't come on at all. The next time I start the car, it will be working. My original thought was to replace the relay, however when I looked in the fuse box there isn't a relay for the HVAC Solenoid, so I don't know what else to do. I don't have any warning lights on and when the blower is working the heat is great.

    Any suggestions?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,048
    >It isn't an SE or anything special.

    If it's a Bonneville, it's already special!

    >Most of the time when I start the it the heater blows, but sometimes it doesn't.

    I suspect the control on the dash was not the problem.

    One most likely point is the blower motor itself. Some are having wear on the commutator so that when it stops it may not be making electrical contact. Then when the dash control and the programmer on the heater box say blow, the blower motor doesn't move. When the car hits a bump, or something vibrates the motor, the commutator makes contact and the blower starts working while you're driving.

    Next time your start the car and turning the blower speed up doesn't result in any air movement, use the toe of your foot on the right side of the hump and tap upward against the blower housing; keep your foot back toward the firewall. Most likely the blower will come on. Keep the key on while you do this.

    The snap connector in that area may have a burned contact--check it first by disconnecting and looking for burning or melted plastic.

    There also is a blower control module if you have the automatic control AC unit (C69). These are next to the blower and control the speed using a power transistor.

    The blower can be replaced easily by removing the plastic panel under the bottom of the dash with a few screws and clips. The blower motor is held in with 3 screws and wiggles out with the squirrel cage attached. Some people say to pull the carpet back from the firewall to allow another inch of room and that will make it easier to wiggle in and out.

    This requires working lying on the floor and across the seats, but several types of blowers are available on the net. Some are much better quality than others. I'd suggest to look at some of the choices. Click through their online parts list to get to heating and cooling and then to blower motor.
  • vike2vike2 Posts: 4
    This all started when the battery was changed, with no keys in the ignition. ac heater monitor in the dash started blinking the temp and then goes to out side air temp, which does not blink. no hot heat, just warm. unhooked the battery cables tied them together to drain the system, had 4 volts to 0 volts. did not reset the system. programmer moving duct doors correctly, acutator has a hard spot in it and hangs up, (new one on order), when moving rod. can move the rod manually thru access hole in the glove box, get cold and hot air to work properly then. but temp still blinks on dash monitor. any ideas how to correct monitor temp blinking, changed the monitor from one car to another and still blinked. lost and need ideas.
  • I have a 1993 Bonneville SSE. A few weeks ago I changed the battery and the same thing happened to me. I have not figured out the perfect solution, however this has been working for me. Set the temp on the lowest setting which is 60 and on AUTO. Mine blinks for about 20-30 seconds and then stops. When the blinking stops then you can put the heat up to whatever temp you want and it will work fine. If you start on any other temp besides the lowest the digital readout won't stop blinking and you won't have heat.... What stinks is everytime you turn the car off you will have to perform this procedure. Hope this helps! Let me know if you find the right fix...
  • vike2vike2 Posts: 4
    that helps. does any one know how to put in a new acuator with out taking the dash out? does anyone know if you change the acuator if that will make the blinking stop on the temp? does anyone have a diagram of how to take the dash apart?
  • m20cm20c Posts: 4
    No matter where the digital temp is set to, 60 -- 90, AC on or off, heat comes out the vents. AC compressor is not cycling, check freon .. OK, so I know it is not low. When temp set to 60, no matter what mode it is in, defrost, at feet or center vents, heat comes out. Could it be the heat divertor? And if so, is it located behind the glove box? What steps do I need to go through to get access to it?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,048
    Do you have a manual system or the dual control system.
  • m20cm20c Posts: 4
    I do not have dual control. Electronic digital control of AC and Heat.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,048
    Yours may look like this...

    At the middle left of the picture is a white arm with a thin threaded rod that goes to the right about 5 inches to a little white plastic arm that is part of an actuator.

    By taking off the hush panel under the dash (3 screws and two taps at the firewall) and maybe taking off the glovebox door, you can see that arm. By moving it while the key and heater are on, you should see it go right and left to change the blend door to give the temp you want. It may be unsnapped from the arm. It just snaps on sideways and you would have the door at the left inside the heater on full heat and the digital temp control at full heat request (90) and then snap on then.

    This picture may help more. These have had the dash removed for some kind of work. Yours can still be reached but will not be this easy, depending on the year.

    The actuator may be burned out or the gears cracked. They are available at or You'll need to be very careful you get the right one for your car. IF it is bad, you can take the actuator off with two screws-not easy to get at one, and check the part number on it. Put that part number into the blank on gmpartsdirect or rockauto and it will give you the right replacement.
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