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Pontiac Bonneville Heating/Cooling Problems



  • I bought this car cheap because the former owner was sick of driving a cold car. Read this forum and went right to the vacuum connector and removed it. Spliced those vacuum lines back together using the recommended 1/8th inch hose pieces as was discussed earlier and VOILA!!, everything now works as it should! Replaced a few rotted vacuum lines under the hood as well.

    Once pulled apart the nipples in my factory connector were found to be very soft and apparently had caused all of this car's ac/heater problems too.

    Thanks, guys!

    Tom in Michigan.
  • kevin27518kevin27518 Posts: 3
    I had the problem with my display flashing. I also had change my battery during the past few months. I have found a simple fix!

    1. Locate your outdoor temperature sensor (open the hood and look down in front center of the radiator)

    2. Disconnect the wire from the sensor. It just unplugs at the connection.

    3. Start the car (no outdoor temp) turn the ECC on the inside temp flashed as it did for me before.

    4. turn the car off after about a minute or so.

    5. Reconnect the temp sensor and start the car and GOOD GOD no flashing light and the heat and a/c works!!!

    I can't remember if I turned the ECC off before turning the car off, but I think I may have. Try it both ways if you need to.

    It has been about 2 months or so since I did this and it's still not flashing.

    Tech told me that you have to have the ECC off when you remove the battery so that this does not happen again
  • I dont remember when it all started but my bonne wont put out any cold air. Ive got adequate r134 refrigerant but still no cold air. When I turn the A/C on and turn the temp all the way down I can hear the compressor kick in. My temp display flashes on the ECC also. My mode controls aren't working properly either, seems only to come out at the floor and defrost vents. One last thing, when I travel on the highway everything could be off and im still getting hot air out of the floor vents. Really sucks in this hot weather!
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,694
    Couple of questions are have you checked the flow of air out the defroster to see if that air is COLD after it's run a while.

    Have you checked to be sure the compressor is turning in the middle part while the motor is running and AC controls trying to engage it?

    Have someone switch the AC on while you're watching that compressor belt running and see if the middle part with the three strips starts moving?

    IF so, are the tube going into the AC unit back by the firewall both cold? With the outlet one to the dryer unit colder than the inlet? IF so you have a good charge of freon.

    Check the front of the firewall around the heater blower motor for broken plastic that's letting in air from the hot engine compartment. Some have had trouble with the plastic there breaking from age and heat.

    Your AC digital readout is flashing for some reason. Most of the time it's low freon OR it's a bad actuator motor on the doors inside.

    I'm betting freon. Was the compressor running when you measured the freon pressure on the low side?

    This message has been approved.

  • I ran it for awhile and still heat coming out. I haven't visually checked the compressor but the oil pressure gauge goes up when I hear it kick in. Yeah the a/c lines get cold. cold enough to condense water on them. Ill have to check the plastic cover later because my wife took it to work. Where and what does the actuator motor do? The freon pressure was about 50 PSI at an ambient temp of 85 degrees.
  • kevin27518kevin27518 Posts: 3
    edited May 2010
    Try the fix from message #163 and see if that helps
  • tried it.... no luck.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,694
    edited June 2010
    If you have a dual temperature controlled system, you have two actuators, one on top of the HVAC box for the passenger and one in the programmer that sits next to the HVAC box. I would expect one of them to be working...

    But. Take off the hush panel underneath the dash on passenger side and take off the glovebox door, if you can.

    The bottom one, a white arm of plastic snapped onto a rod with grooves, should be all the way in to the left.

    Top actuator and bottom actuator arms circled...

    This message has been approved.

  • i have a 98 sse...and ive been experiencing electrical problems for some time...bout last winter i had no heat due to a bad blower motor moduel... i replaced it with 1 from a junk yard and it was working fine...but i would always hear a kind of vaccum noise coming from the passenger side even when the heat or ac was off...and about a few months ago i noticed that my battery was being drained... ive replaced my battery and my alternator is excellent...i have to unscrew the negative on my battery daily so it doesnt die on me...and i can still hear that vaccum noise...especialy when i rescrew the negative and start my car...does anyone know what the problem may be...i would greatly appreciate any advice possible
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,694
    Is the motor running when you hear the vacuum noise?

    Take off the underdash cover and actually listen closer to find the source to see if it's the black tube coming through the firewall to the right.

    If it makes the noise without the motor running and with the key on, see if one of the two actuators that are electrical is running. They have a little electric motor that moves the arms to adjust the vents. The top one cracks a gear and the motor might be running trying to adjust. BUT it should turn off when the key goes off because there's no power to it. I'd have to check the factory service manual but I believe that's the case. What happens if you press OFF on the AC controls while it's making the noise?

    This message has been approved.

  • greasemokeygreasemokey Posts: 2
    edited June 2010
    when i press the off button it goes off...but i can still hear the vaccum noise...i have the electronic temp control so when i start my car it flashes on and off...and when i turn my car off to run into a store or something and come right back..when i start my car i hear the vaccum noise_my temp control is flashing_and my battery is some what drained...just might have to pay that $85 per hr to see what the problem is...damn
  • nocargtxnocargtx Posts: 5
    Got 98 bonneville digital ac controls and ac works but air comes out only two places--windshield and floor. Changed dash control and vac programer and still same issue. Any ideas???? Is there a default and air comes top and bottom and no where else when there is a problem in the system?
    Thanks for any help!!! :(
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,694
    Let me remind others to diagnose the problem before replacing parts.

    Three possible problems:
    Bad electric controls from dash controls?
    Bad plastic connector on programmer box?
    No vacuum from under hood?

    The default for no vacuum is that the doors in the heater box are left in defrost mode (which bleeds some air to the floor) so the windshield can be cleared for safety.

    There is a common problem with the plastic connector on the corner of the programmer in cars of your era. The plastic softens and sucks shut when vacuum goes through each of the 5 little tubes. There was a black plastic nipple inside the connector that is often blamed.

    Bypassing that connector with little tubes to carry the vacuum from the internal plastic tubes to the external ones (different colors in some cases) will fix the problem.

    I have read a couple people with no vacuum from under the hood. The plastic tubing starts next to the big brake booster hose on the back of the upper intake manifold. There are soft rubber connectors, people said, connecting the hard plastic tube. The soft rubber vacuum hoses can deteriorate after 10-12 years of heat and aging. Check the connectors for cracks, hardness, or holes. There will be connectors at the upper intake, at the T just in front of the accumulator for the AC (take off the relay cover over the MaxiFuse center), and at the connector on the reservoir under the fender in front of the passenger tire. Check that cannister for cracks. If you pull of the hose, then reconnect and run the motor, removing the hose should give you a good whoosh as air rushes in to fill the vacuum.

    If the AC control is bad, most people say it just is obviously dead or crazy.

    My testing for vacuum, was run the engine, then turn it off and leave the key ON. Switch between various settings on the control panel. After a few seconds you'll hear the vacuum diaphgrams sucking in to move the doors. Also you can remove the hush panel on the driver's side, and when you switch the controls, you can feel the vacuum diaphgram move with your fingers on the engine side of the diaphragm. The back of it is open so you can feel whether the thing moved. You'll have vacuum for about only 30 seconds or this if your hoses under the hood are all okay.

    There are 3 vacuum motors. One above the accelerator slowly closes to give recirculated air taken in from above the driver's feet.

    One closes off the floor opening and forces air upward to the dash or defroster openings. This one also has a second vacuum tube. When these are working, it leaves the floor vent partly open for windshield and floor with lots of air to the floor but air going out the defroster.

    The remaining vacuum motor operates a horizontal axis door that closes off the flow to the defrosters; this forces the air out the dash vents because the floor vent is supposed to be closed off.

    To verify that the blue hose to the defroster door was getting vacuum, I switched the hose to another vacuum diaphragm and felt that motor move closed when AC dash was asked for.

    This message has been approved.

  • nocargtxnocargtx Posts: 5
    Thanks for your reply--have changed some elements mentioned and also have vac to the junction connector. Did not check to see if connector was open. I have no vac coming out any of the other tubes to the various actuators on the main box. I only know my source of vac to the connector from outside is good and open.
    My main programer box was replaced last year--the lever plastic gears were stripped--it works fine now. Temp changes from cool to hot as it should. My temp light fashes since replacing vac programer.????
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,694
    edited July 2010
    > only know my source of vac to the connector from outside is good and open.

    TAke a long piece of plastic tubing or rubber vacuum tubing. Connect it to the black incoming vacuum and connect it to the blue tube's connector for the dash vents. See if it will pull that diaphgram closed. That would check for full vacuum power in the black line going to the programmer box.

    I know of one person who said they were able to get the plastic coupler apart and open up the holes successfully. I would just jumper it with tubing from inside to outside.

    The only odd thing is you're getting none of the vacuum motors to work.

    >light flashes

    Does your car have a separate electrical actuator on top of the HVAC for the passenger side air blend door? Is that motor stripped or not working? Is it plugged into the main programmer box?

    This message has been approved.

  • nocargtxnocargtx Posts: 5
    My car does not have a seperate act. for passinger side--has one program box with act arm at top of box and it works OK as best I can tell. Temp goes up and box switches and goes other way and temp changes.
  • Fixed the dern thing--cut vac lines on the two part connector and connected them with small black hose to by pass factory connection and everything fine--works like it should. Apparently the connector does not seal tight enough for vac not to leak.
    Wife has cold air like it should be and life is better!!!!
  • bahappebahappe Posts: 5
    Could you please provide me a graphic of this because I need to check and probably change one or more of the actuators. IT would be of great help.
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 17,694
    Of what do you need a graphic? The HVAC box showing the upper actuator for the passenger air and the lower which is part of the programmer box?

    What is happening with your car? Maybe that will tell me what you need to check?

    This message has been approved.

  • bahappebahappe Posts: 5
    The air works on the passenger side but not on the drivers side. I removed the glove box and hush panel and checked to see if both of the actuators were working and both of them were. I then assumed that there must be actuators on the driver's side. I then went to the driver's side and removed the hush panel. Looked up in there and it appeared that there were 2 actuators in the middle of the console. I looked to see when i turned the A/C and Heat on if the little silver circle was moving and on the actuators. One of both of them appeared not to move either way except when I shut down the car and turned the car back on... When A/C was heat still blowed out the drivers side was still hot and cool on the passenger side. Please advise. I guess i really may not need a picture after all...
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