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Pontiac Bonneville Heating/Cooling Problems



  • Hi,
    I have a 1996 Boneville and was told today I need a A/C programmer. I can't find what I am looking for. Did you ever find a part number and how much was it. Where did you buy yours?
  • I found mine in a junk yard. What I found was that it is a very popular item, and every junk yard that takes them out and sells them did'nt have any. I finally found a yard where you have to remove your own part, and they had one which I paid $40 for after I took it out. It was'nt hard to remove since I just cut all the hoses and wires. I found out from the dealer that the same part fits all bonnevilles from 1996 thru 1998. Good Luck.
  • richard82richard82 Posts: 4
    My 1998 Bonneville SLE has the automatic climate controls. The heater, defroster, and blower motor work fine. After running the A/C for 30 to 60 minutes, cold air stops coming out of the A/C ducts. As per previous advice, I checked the compressor clutch operation and it works fine. It actually seems like the cold air is then coming out through the heater vents! After the car sits for awhile, the A/C will again work, but only for the same short amount of time. I've checked for broken wires and blown fuses with no luck. I've seen problems posted in the forum that mention having A/C, but no heat. My problem is just the opposite.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 22,059
    The the cold air coming out the defroster openings? Try putting the temp control all the way cold and see if you aren't getting the cold or hot air out the defroster. That means the vacuum lines at the corner of the programmer are being blocked by sucking the plastic into itself and closing off for the line going to the door for the dash air ducts.

    The fact that everything works right at first is a good sign. Are you in a relatively cool climate? I think high temps in the car sitting in the sun help deteriorate those plastics faster. The connector can be cut off the tubes at the corner of the programmer (controller) box down under the dash. Those loose ends can be connected with pieces of aquarium tubing or with 1/8 inch rubber gas line pieces. I did it on mine.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • richard82richard82 Posts: 4
    Thanks for the help. I think the problem is solved! Besides removing the plastic pan under the glove box, I also removed the glove box door to give me more access. The female plastic connector would not unplug because it had actually melted onto the male connector on the programmer. Without disturbing the controller, I was able to cut the male and female connector assembly away from the unit and cut the vacuum hoses on each side. I then spliced the colored hoses together using 1/8" vacuum hose slipped over each of the cut ends. It worked great! Make sure you have spliced the correct hoses together, using the cut off connector as a guide. I was also greatly helped going to the link;
    This site has good instructions and color photos of parts involved.

  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 22,059
    That probably is the site I was going to refer you to if you decided you wanted to try the squishy connector fix. Some people have gotten it apart and reamed out the openings and then put it back together. But usually it rips. I considered putting it back together with silicon caulk/glue would seal up nicely. But on mine I used the gas line piece over the matching ends.

    Amazing what a little piece of deteriorated plastic can cause. A lot of people replace the $450 programmer box and it wasn't the cause at all for their problems.

    Thanks for reporting back to let others know what you found and what worked!

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • I have the exact opposite problem from what I have seen so far. My heater works outstanding, even when the A/C is supposed to be on. I had the AC compressor replaced last summer and the mechanic lifted the hood and placed a thermometer and showed me that under the hood the air was blowing between 55 and 60 degrees. Plenty cold. The problem is that after several hours of trying different things, he could not for the life of him figure out why it was still blowing extra hot inside the car. The remedy was to get a pair of vice grips and clamp off the hose that was allowing air into the car. So throughout the summer I didn't have AC, but at least the hot air was limited. Needless to say it was a very LONG, HOT summer.
    So when the winter came along, I simply took the grips off and let the hot air flow.
    Well now it's summer again and I still have extra hot air. I have automatic climate control and regardless of what temperature I set it at, it still bows nothing but hot.
    I have contacted the 2 biggest auto parts suppliers in the KC metro and they say they do not have a Automatic Climate Control head unit for sale. I can you search within 600 miles for a part that fits so many cars, and not have one?
    And I do not even know if it is that part that is the problem.
    If any of you have experienced this problem and or can give any insight, it would certainly be appreciated.
  • richard82richard82 Posts: 4
    It sure does sound exactly like the problem I had. Thanks to help I received on this site, I found the problem was indeed the vacuum line connector behind and under the glove box. You sure don't need to spend $400.00 on a new controller. If you can cut away the male connector part from the bottom of the controller, then cut the vacuum hoses behind the female (clear) connector you can slip 1/8" rubber or neoprene hoses over the small colored vacuum hoses and eliminate the connector entirely. My Bonneville is a 1998 with 70'000 miles on it and my connector was melted together resulting in softened and plugged ports in the vacuum connector. Hope this helps you, it sure worked for me. :mad:
  • mqueen1965mqueen1965 Posts: 1
    I just purchased a 1995 Bonneville and I love the get up and go. the AC seemed to work when I test drove it. Now it blows nothing but hot air even when the system is off. My question to you is did you get yours fixed? I need to drive 500+ miles for guard and it gets hot. Should I bother charging the AC unit until the heat problem is fixed? Any help would be great.
  • Sorry it took me a week to get back.
    I haven't got the problem fixed yet. Tuesday morning May 27th I'm taking it back to the shop that replaced the A/C compressor 2 years ago.
    Hopefully they can figure something out. Or at least clamp off the hose allowing hot air to blow in. With it being 13 years old now and with 140,000 miles, I'm real hessitant to spend more than a few hundred on a repair. It has leaked oil ever since I got it. I keep it changed regularly. I was pitting Lucas Oil Heavy Duty Oil Stablalizer in between oil changes. But at $11 per, and would do that twice between changes. So now I just went to Sams club and boought a case of Mobil 5000 oil. It has increased my mpg from 22.5 to just over 24. And that has been for several tanks in a row not just once.
    Anyway, I'm getting off track. After I take it to the garage, I will post here Tuesday night with an update.
  • smayensmayen Posts: 2
    how did you make out on changing the actuator? was it difficult?
  • smayensmayen Posts: 2
    Hi, the a/c in my Bonne isn't blowing. The hoses under the hood are cold and the compressor turns on, but it not blowing through the vents. What I have noticed is constant hot air blowing out from the floor vents. I did some research and think it may be the actuator, but not 100% sure. Has anyone experienced anything similar? Or have any suggestions? Thanks.
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 22,059
    Are you able to change the path of the air to the defrosters, then to the AC vents on the front of the dash?

    If so, you may want to take off the hush panel above the passenger's feet (about 5 little screws and taps) and look for the brass colored screw rod that clips to a white plastic arm coming out of a programmer box. Either the vane inside is stuck or the arm is snapped off the screw thread rod or the programmer box not working the rod.

    I believe the rod that controls the driver's heat is the lower one. If you have automatic air with a pssenger control, that's the upper one way up high on top of the box...

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • After spending 5 hours at the garage, they still couldn't figure out the problem. The solution this time (instead of just putting vice grips on the hose that allowed hot air into the car, like they did last time) was to disconnect the heater hoses. So now I atleast do not have the hot air blowing on me all summer. But still, it will be taking it back to the garage twice a year for as long as I have the car.
    If anyone in Kansas City knows of a shop that could fix the problem for good, and it wouldn't cost me several hundred dollars, please let me know. Thanks
  • ralph22ralph22 Posts: 8
  • ralph22ralph22 Posts: 8
    I noticed a few people having this problem. I have a 1998 Bonneville, but I think the cars are the same. Behind the left vent on the glove box is a duct. On top of that duct is a metal rod about 3/8in and 6 inches long. An actuator moves this rod which determines if you want cold or hot air. If the rod is moved towards the passenger's side door, you get hot air and the other way for cold.You have to take out the ac programmer and the box against the fire wall. I had to change my programmer a few months ago, and I put 2 ft of extension on the wires attached to the top of the programmer, so removal was not a big deal. Anyway, you now can get your right hand up and over the vent duct and feel the metal rod. Before moving the rod, set your ac to full cold. Now push the rod towards the drivers door. It will be hard to move because you are forcing the actuator( maybe a worm gear or something). You should now have cold air all the time. I read about one person who managed to get a coat hanger attached to the rod and ran it thru his glove box so he cold move the actuator and get hot or cold. If you have to cut the hoses to remove the programmer, you can get a hose that fits right over the cut hoses. Good luck.
  • steve180steve180 Posts: 5
    I have a 1996 Bonneville with electronic heat and air, no matter what mode i set it on, it aways blows out from the top defrost vents and floor vents. I can't get the dash vents to work at all, hot, cold or even when automatic mode is shut off. The arrows move on the electronic display but it never blows from the dash vents. Any ideas on what it could be. I have looked for vacuum hoses but can not find them or the right ones.

    Thanks Steve
  • imidazol97imidazol97 Crossroads of America I70 & I75 Posts: 22,059
    You probably do not have vacuum to the internal controls. Most likely is that your vacuum storage tank is on the firewall built into the Relay Center. it's right in front of the driver. There is a small nipple at the bottom and there's supposed to be a vacuum hose connected to it. Often this gets pulled off by reaching with an arm to get to the spark plugs in back, e.g.

    i think the 1992-1996s had that setup. Then 1997-1999 had the tank under the front fender.

    If it's not there on the firewall, look under the right front fender in front of the wheel. Lie on te ground and look up. sometimes the connector goes bad that snaps on or the tank splits with age or injury. If the tank is there pull of the hose with the motor running to see if there's vacuum stored in the tank--it'll whoosh when you pull it off.

    If that doesn't work then there may be an internal problem under the dash. There's a programmer box with a 5 tube coupler made of plastic that has little rubber layers inside that soften and suck in and block the vacuum--but you usually will hear the lower dash vanes move when you put the settings on heater and on bilevel with the motor running. Try running the motor and then turn it off but leave the key on and switch between settings and see if you hear the vacuum motors move. If not you probably don't have vacuum coming inside at all.

    Check for the engine and storage tank vacuum lines and then I can give you links for the inside problem and cheap fix.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • nealcnealc Posts: 1
    have no ac every thing under hood is working.but it blows hot inside car
  • steve180steve180 Posts: 5
    I found the canister, it was under the fender on passenger side front. I pulled the hose off and got a little woosh, not much. I did try with the car motor off but switch on and you can't hear anything moving under the dash when i change modes. I even put it on just floor vents and it will not change, still comes out from defrost vents and floor but not the dash.

    Thanks for your help, i will try anything you suggest
  • 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 & I75 Posts: 22,059
    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.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • 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 & I75 Posts: 22,059
    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

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • 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 & I75 Posts: 22,059
    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.

    2015 Cruze 2LT, 2014 Malibu 2LT, 2008 Cobalt 2LT

  • 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
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