Pontiac Bonneville Heating/Cooling Problems

m20c · April 2009

Thanks for you help!!! I'll dig into it and let you know how I make out.

m20c · April 2009

Thanks for the help, the actuator was stuck mid position, just freed it up and started working again.

imidazol97 · April 2009

Great. Thanks for reporting back.

vike2 · April 2009

thanks everyone. this will be my last post. unfortunately my 1995 bonneville had a front end collision, it was totaled. i am sad but no one was hurt thank god for that. i loved my car and am very sad about this thank you all.
vike 2

vike2 · April 2009

I will keep checking in on this site once in a while to see if I can help with anything.
vike2. thanks again.

bonnarizona · May 2009

I have a 2000 Bonnie SE, the passenger side blows super cold air without any problem. However the driver dash side only blows hot, with just a barely noticeable smidgeon of cool if at all.
It's a dual zone electronic with digital readout, the rear passenger outlet is also warm.
Air flow seems to switch areas selected without any problem. about 3 months ago, autozone guy, put in some freon in one of the 2 lines that run parallel to each other alongside the fender wall, it seemed to help. just a tiny bit, nothing to be elated about.
Asking the passenger side outlet to cool the whole interior, just won't do it, and pointing the outlets toward the driver for some relief, won't do it either.

Bottom line--Drivers side does not cool- (Nor do the middle ones on dash).

PLEASE HELP, can't afford a mechanic and need to drive to LA to visit with my son who is on his 4th tour to Iraq with the Marine Corps, the interior gets very hot for my wife and we must drive during the day from Arizona .

I anyone can tell me how to tackle this problem, we'll be forever grateful.

If some one can tell me where to look and how to get to it. I have no problem tackling it.

THANKS IN ADVANCE FOR YOUR HELP.

imidazol97 · May 2009

Most 2000+ cars with this problem find their refrigerant charge is low. Because of the flow of coolant into the evaporator coil, the side that gets the coolant first is the area of the coil over which the airflow to the passenger side passes. So that air gets cooled while the warmer side of the evaporator doesn't cool the air going to the driver.

If you have some expertise, you can get a 134a can with a gauge at Walmart or other store. Do not get the ones with sealer, dye, superfreon, in them. I bought a separate gauge they had and just buy the plain cans. Recharge with the motor running and the heater fan blowing on high to the pressure they indicate on the gauge.

You'll probably find your cooling is back.

If there's an actuator problem inside the car that moves the vanes that control the air, that too can be changed by a fairly knowledgeable home tech type. If when mornings are cold and you have the heater on, both sides can heat and adjust with heating occuring, you probably just have low refrigerant. If the actuator is slipping, you may have trouble with heating settings.

bonnarizona · May 2009

Thank you very much for your prompt response, I will get these items and hope is just a coolant issue.

IF is an actuator problem (hope not) how difficult is it to remove the dashboard to get to the actuator ?? and if damaged is it possible to leave it in a permanent "cooling position" ?

We wont see winter here until about January
THANKS AGAIN

imidazol97 · May 2009

The actuators are even easier to access than they used to be.

Remove the hush panel and be sure it's the actuator that won't work by watching as the settings on the dash are changed with the key ON. A couple of screws and the new actuator slips on. Of course there's an electrical connector. I can supply a graphic if it comes down to that. But I'd bet your actuator is adjusting the heat temps for you, indicating it's okay and the problem is in the low charge. But the actuators do have a failure rate.

bonnarizona · May 2009

THANK YOU SO MUCH!!!!!!!!!!!!!, I happened to drive by a service shop and decided to stop and inquire about the cost for 'topping off" the freon. Just as you said, Freon was way low, charged me $45.00 and problem solved, I figured I may have spent this much at least if I had tried to do it myself.
Now I have to watch how cold I keep it, so my face doesn't freeze off : )
I want to Thank Imidazol97 for his quick and very effective help !!!!!!!!!!!!!!!!!!as well as the people who put this website together.
God bless You guys !!!!!!!!!!!!!!!!!!!!!!!!!!!!
I am on my way to California this friday.
Thanks again

imidazol97 · May 2009

thanks for coming back to let us know what worked.

Actually a can of freon may be a few dollars and 10$ or so for a gauge that's reusable. Doing a quick connect to the low pressure side with the motor and system running on a 70 deg day, and you turn on the freon in the can let is slowly recharge the system until the pressure gauge gets the needle to the top of the green section. Then quickly turn off the feed, remove the screw on connection, replace the plastic cap to keep the connector clean and you're done.

But it does require some experience with working on the car and some confidence. That varies with the person's past at working on cars.

If I needed air tomorrow, and if I wasn't certain about what to do, $45 would be a bargain. I'd say that shop deserves your business the next time you have car trouble. They didn't rip you off.

muscle1970 · May 2009

Hi...I have a 2005 Bonneville, and it is doing the same thing. There has been a lot of mention of the accuator, and some say that you can access it through one of the vents. Have you had any luck at repairing this problem? I, like you, cannot afford the expensive repairs. Especially if there is an easy way to fix it myself. The dealer estimated that it would take 8 hours labor.

imidazol97 · May 2009

Is it a dual zone system with different temps for driver and passenger?

But first check the coolant charge. That seems to be the most common problem: loss of freon charge. It still cools, but not as well. And the cool part of the evaporate is where the air to the passenger goes through.

dannybailey · August 2009

I have a very strange problem happening with my 1996 Bonneville SE.

Example: I start my car, turn on the A/C it blows cold air. However, when I shut my car off and wait just about a minute and then turn it back on it blows hot air. Then if I shut it off again and wait a minute restart it then it blows cold air again. I've tried this over and over and it is consistent everytime. What ever temp it was blowing at the time I shut off the car the next time it will blow the opposite temperature.

Plus it takes about a minute for it to cut over each time I start the car up.

Also when I turn on the blower it seems to always just blow air at my feet even though I've got it set to blow through the vents, but after about 4 to 5 minutes it starts to slowly blow through the vents and then increases to normal air volume.

Has anybody ever had the same problems and if so how did you fix them? Photos would be greatly appreciated.

imidazol97 · August 2009

You are going to have to diagnose what's wrong.

>Also when I turn on the blower it seems to always just blow air at my feet even though I've got it set to blow through the vents,

If you have automatic temp control AC,

If that's what's making it hot, you're in luck. But check to see if there's cold air coming out the defrost. If you're in a hot climate you won't feel any cold from it at all, but the cooler is still working under the hood.

If the air is coming out the defrost and heater, you have lost vacuum to the interior. Since the vacuum returns!!!! after a few minutes, check the vacuum liine under the hood. On your 1996 I believe that starts at a little slick plastic tube (1/4 inch) that comes out of the upper intake manifold right next to the big black rubber hose going to the brake booster diaphragm.

Follow that line. Feel the ends. Feel for cracks. It goes to a one-way valve over on the passenger side near the dryer unit for the AC and then there's a branch at a T. One goes to the storage tank under the fender in front of the right wheel. Check that tank for cracks losing vacuum and check the connection.

Check all lines on the motor for cracks and leaks due to age or rot. They may be affecting your vacuum.

The other branch of the T goes to the inside.

Run motor and then pull of the connection at the reservoir under the fender to see if there's a big whoosh as air goes in to replace the vacuum.

Otherwise check under the passenger dash. Remove the hush panel. Remove the door for the glovebox. Check for vacuum there at the violet line connection to the black line coming through the dash from the engine compartment.

Problem may be same as here.
http://www.imcool.com/articles/aircondition/fix_vacuum_line.php
Use 1/8 inch internal diameter rubber gas hose to connect the lines to bypass the clear plastic connector that sucks shut after it softens. Pieces about 1.5 inch or less work fine.

You also might have a vacuum actuator for one of the doors in the heater box that has cracked or torn. When you move the control setting to differnet places, feel each of the 4 vacuum actuators over above the driver's foot to see if they move fully. The back of the vacuum motor is open and you can use a finger to follow its movement or even to push and make each one operate. I believe the blue tube goes to the one that closes the door above the dash vents and makes the air come out the dash vents instead of the defrost vents.

On the other hand:

>However, when I shut my car off and wait just about a minute and then turn it back on it blows hot air. Then if I shut it off again and wait a minute restart it then it blows cold air again. I've tried this over and over and it is consistent everytime

If when the car is started and there's no AC, have the hood open and check to see if the AC compressor is turning. Check to see if the metal AC line is getting cold like it usually does. That would indicate a relay or something might not be turning on. There's a relay in the relay center for the AC compressor clutch. But if contacts burned on it, I don't think it would be as definite in reconnecting like you're describing.

jd0754 · August 2009

I have a 1998 Bonneville air will not come out of the center vents,but from the defrost and floor vents. After sometime it will eventually start coming out the center but will also continue out of defrost and floor. If you turn the fan speed down manually you can here a clicking sound like one of the doors are closing. The longer the clicking goes the more air comes out of the center vents. Just recently had an actuator replaced because we were getting no air from the center at all. Any ideas?

imidazol97 · August 2009

The actuator for the center vents is vacuum operated. It's just like on my leSabre. It has a blue tube going to it. Check for vacuum in that blue tube... when the AC is requested from the programmer via the dash control panel.

Also..., does your car have dual temperature controls? I am not clear from my service manual if a separate temp control is available for the passenger.

The one way to check the vacuum actuator for the AC doors is to use a vacuum line from the heater or recirculate vacuum motors with the control panel requesting floor heat or recirculate. Snap the hose onto the AC vacuum motor and see if it works. Be aware you can feel the backside of the actuators which is open and feel the diaphragm move when vacuum is applied. That helps eliminate a tear or leak in the actuator itself. These actuators are above the driver's right foot. The is one with two leads to it for the floor doors-they close partly when doing windshield/floor-so there's a tube to both sides of the actuator for that one. There's an actuator that rotates high up in the HVAC box to close off flow to the defroster. That makes air coming up go out the dash vents. The heater opening at the floor closes off to make the air go up to the defrost or to the AC dash vents. The other motor is to the left and on the air return for inside air; it draws air from above the driver's feet and uses that rather than all outside air. Be aware that hose has a restrictor in it to open and close slowly; the restrictor is a ceramic that bleeds air through to control how quickly the opening occurs.

If you take off the passenger hush panel and remove the glovebox door, you'll be able to see the electric actuator which moves the temperature door inside the HVAC box. That actuator may be inside the programmer box or may be a separate one up on top. By watching it while moving the temperature so it has to adjust, you can see if the clicking is coming from the actuator.

txcarnovice · August 2009

Have a 2002 Bonneville with the dual zone system, and it is ONLY the driver's side that is blowing warm air, but even that is mostly when the car is up at speed.

Passenger side blows cold all the time.

Driver's side will blow cold when the car is sitting still or when moving a neighborhood speeds, but as you go up to highway, the air gets warmer (though never is fully outside air temp).

Driver's side will blow hot when you ask it to with controls and definitely cools down a little when you turn the A/C on, but is probably 15-20 degrees warmer than the passenger side.

Any thoughts?

imidazol97 · August 2009

The larger number of problems is that the R134a is low on charge. The freon enters the evaporator in the area that the air to the passenger flows over, so it gets the colder metal as the freon expand and cools. The freon doesn't make it to the other side where the driver's air is moving over the coils.

First thing is to check on freon charge.

The other is that some have trouble with actuators. I believe there are three and they are all on the driver's side of the HVAC stack in the middle of the car.

Take off the hush panel, and move the AC controls to different settings and you should be able to cause each of those to move. You can see the axle of the actuator move people say. They are also made for easy remove and replace. Just be careful to install correctly. Some actuators have failed, but I would think that would cause you to have the wrong temperature all the time.

jd0754 · August 2009

This thing is all balled up, does not have dual temp control, put selector on floor setting and it comes out of both the floor and defrost all the time, put on defrost setting and it does the same, put on center vent and eventually it will come out of the center vents, temp seems to be ok I had it at 60 and it was cold, it's just that it won't come out of the right vents.

imidazol97 · August 2009

I think you have bad vacuum in the motor or a leak under the hood.

Check the vacuum hoses around the motor? Do you hear a vacuum leak?

Check the reservoir behind the front wheel underneath. Cracked? One line on it good connection? When you shut off motor and go to it to pull off, there should be a strong vacuum whoosh for 15 seconds or so when you pull off the hose.

jd0754 · August 2009

Thanks a bunch, I'll keep you posted, I am going to have guy that's a Mr. Goodwrench at a dealership around here look at it hopefully this weekend. One more question though, when I finally get the air to come out of the center vents when you shut off the engine it closes the door to the center vents immediately so when you restart the car you will have to wait another 5 minutes for the air to come out of the center vents again, caused from losing vacum?

pickngrin1 · August 2009

Greet'ins all!
2002 dual control..excellant AC from driver's side...FULL BLOWN HEATED air from passenger vents.
All fan speeds operational
All modes operational

But the AC just cant quite do its job fighting with the blistering hot air coming from the passenger vents...even shutting the vent louvers off, the heat still forces its way out some and also out of the windshield defrost vents.

Not a freon problem folks.....is it a bad control? Or can it be a vacuum hose / actuator arm?
Thanks!

imidazol97 · August 2009

There are several actuators on the driver's side of the HVAC box. You'll have to try moving different controls and watching for the axle on each one to turn. I'll bet you'll find one isn't moving. It might be stuck--or-- dead.

There have been a few reports of failed electric actuators all along with these H-bodies.

I can't tell you which actuator is which function. I'll have to see if I have a labelled diagram. My guess is start testing for movements. You'll have one for recirculate, mode choice, driver's temp, passsenger's temp?

pickngrin1 · August 2009

Thanks, that was it! FIXED IT! After removing the glove box I found a small moterized gear reduction box was stuck...I removed it and manually rotated a shaft that must control an air mix door. I could manually go from full hot to full cold easliy. After opening this small moter/gear box...abut the size of a cigerette pack...I was able to lube and it started working again..the dual system works just great for now!
...reading through all these posts really helped!
-Pick

imidazol97 · August 2009

Great! Thanks for coming back to post what worked for you; that will help others know what to test or look for if they have a problem.

>I could manually go from full hot to full cold easliy

Was that on top of the HVAC box?

breez22 · August 2009

Ok i read through all the post's, and i just got my car back from my mechanic. i've gotten some great info on this my blender door was stuck on the hot side. The mechanic moved it to the cold air side. I have not tried much but this gives me some great ideas. I would like to know does the actuator actually rund the blend door? Are the 1999 models actuator in the same spot on to as the 1997 that the pictures were on? Thank you in advance.

txcarnovice · August 2009

IMIDAZOL97

Have to thank you for the advice. Got the freon topped off and the system is working great.

Still working on finding the leak (had a dye included with the top off just to see if we can find it), but worst case, I can spend $30 topping it off couple times a year. Definitely worth it, and better than spending a bunch of time and money on suggested fixes from the repair shop that sounded like a whole lot of work for nothing.

imidazol97 · August 2009

only if you find an actual leak location would I consider repair. Then I'd do it only if the leak was more than once per season. There are some sealers that I read about people putting into their system as a do or die.

steve04bonny · September 2009

ok ill try to explain this the best i can when you start the car sometimes the ac will work great then out of the blue it will start blowing warm air sometimes when it does that you can put it in netural and rev it and it will blow cold but only sometimes
sometimes it will switch by itself to ac off and pushing any buttons on the switch will not help it just stays ac off now when it first started this you could push the seat memory switch on the door and it would turn the ac back on but now it wont now its like if it is on its on and it may stay on for a second or untill u shut the car off then again it may just switch to ac off and start blowing warm air again to no avail it now seems that if it starts blowing warm air and the ac off is not lit and you put it in nutural and rev it it will make it say ac off and the door switch now seems to do nothing for the help of turning it back on as well im just not sure where to go with this problem i have a very extenstive background in autos but nothing like this have i ever seen please help soon

steve04bonny · September 2009

oh also not sure if this is related but the speedo stopped reading correctly as well sometimes it is just off sometimes it will go to like 20 or 40 and stay there other times mostly it will just stay on 0 however the heads up display reads correctly all the time all other gauges seem to be fine just the speedo the odomittor and trip all work yesterday my wife drove it to work it stayed off almost all the way it did switch to ac for like 5 mins after she shut the car off and started it but then the ac off lite came back on and stayed that way till she started it 12 hours later on the way home??

mikesuth · September 2009

2000 Bonneville SLE
Dual Climate Electronic controls
I have read through this thread a few times and have tried several things. First, I topped off the freon but to no avail. Then this afternoon I checked the bleed doors and they were fine. I found 2, one on either side of the main console in the back. I found where they were, then I played with the thermostat to watch how the actuators reacted. I then removed the actuator units and manually turned the doors, just to double check they were opening/closing the door to the min/max.

So now I'm stuck. What else could it be?

rockoh · September 2009

I have a 97 Bonneville Se with an acceleration issue related to the A/C-Heat blower vents. When you are running either a/c or heat and accelerate, the blower vents on dash switch over to the defroster vents until the acceleration stops. It then goes back to working normal. There is no issue with hot changing to cold or cold changing to hot, just vent change over. This system is a standard turn dial controller without digital functions. Any suggestions? I believe it is a vacuum issue but cannot seem to figure out where. I even had the dealer charge me for 6 hours of labor to say they could not find anything. Needless to say, I do not use that Pontiac dealer for anything anymore. Any help would be appreciated.

ralph22 · September 2009

I can give you a suggestion in regard to the change due to acceleration. Your programmer (which does nothing more than select vents) works off of pneumatic pressure (or vacuum more correctly). It gets its vacuum from the intake manifold. Therefore, when you accelerate, manifold pressure drops. Now, this is the way the system works everyday in everyone's car. Why this loss of vacuum is affecting your system more than it should be is a mystery to me, but its the only thing I can think of. Try tracking down the vacuum hose and see if there is a partial leak. My hose was on the front of the engine on the driver's side, and mine was leaking too. On my car the hose went thru the firewall on the driver's side.
Maybe this will help. Good luck.

imidazol97 · September 2009

Ralph's on the right track.

Your unit uses vacuum to control the diaphragms that are inside the car. Each of these diaphgram motors is a rubber/plastic diaphragm that can tear or crack and leak air in which makes the vacuum the programmer (switch that controls the vacuum) ineffective. There are four of these on the driver's side of the dash. There is a plastic cover under the dash taht comes off with a few screws.

You might have a leak in one of the diaphgrams, but you say it occurs in AC or heat. Those use different diaphragms.

So back to basics. Your tube for the vacuum comes off the top of the motor (take off the plastic gray cover over the top by removing the oil filler tube--grab with hand and twist to unscrew the spout not the cap). Then look on the back firewall for the 1 ft diameter brake booster. Follow the big tube from it to the motor. Right next to that is a little plastic tube coming out. That's your vacuum line to the inside.

That line may be cracked, aged, rotted and leaking air in near the motor due to heat.

Follow that line to the passenger side (it goes in a bundle of electrical wires) and you'll find a connection at a Y where one line goes to the inside of the car and the other goes to the front of the car under the fender to a small plastic tank. That tank may be cracked and leaking in air.

There is a one-way valve in the line from the engine. It goes in a bundle up behind the alternator then the plastic line goes up over the accumulator and downward behind the wheel well. The valve is right there in a rubber section of the line. It in the line toward the motor and keeps air from going from the motor into the passenger compartment side. That valve may not be working any longer. That would let lower vacuum from the motor add air to the passenger side when you accelerate and the motor loses vacuum because you've opened the throttle plate wide.

There have been a few comments about leaking air around the upper intake manifold where it bolts to the metal lower intake. But you don't mention any rough running at times or fast idle, which would be symptoms if the upper were twisting and leaking air in at certain temperatures.

Something to try is run the motor and turn it off. Then leave the key ON and push buttons to select different settings on the HVAC unit. With my 1998 I can do that for about 20 seconds or more of listening to the vacuum motors pull the different plates in the box to change the air flow. If yours does not retain vacuum in the storage tank under the front fender enough to do 5 or 6 change cycles that might indicate a leak in a tube after the one-way valve such as the tank at the front or a part inside the car.

cmazeo · October 2009

Just bought a 2000 bonneville from an auction and the hvac doesnt work at all. No display in the window. Buttons dont light up. Checked the fuses under the hood and under rear seat. None are blown. Had a mechanic scan but no error codes for the hvac. Gotta few other problems too but this is the main one. Thans for any help.

imidazol97 · October 2009

You may not have found all the fuses. The head unit may not be working. It may not be plugged in. Please wait and I'll check my 03 service manual for fuses tomorrow morning. Hopefully it's just a fuse.

cmazeo · October 2009

ok thanks, The interior lights on the unit do come on but not any of the lights on the buttons ( defrost, auto, rear, display... etc) . You mentioned the head being unplugged .. not sure what the head is but if it was unplugged would it affect the interior lights on the unit ?

imidazol97 · October 2009

In the rear fuse block,
#33 HVAC
#34 Ign 3
#25 Pass MDL

cmazeo · October 2009

#33 and # 34 checked out good, #25 has no power feeding the fuse at all. Thanks
..............also I pulled the unit out and checked the connector in the back where it slides in for power using a grounded probe light and I had pwr on about 4 of the leads on that connector. That unit is hvac unit is really flimsy.. I think I'll try and find one at the salvage yard and replace it .. maybe that's the problem.
will let you know ... thanks

imidazol97 · October 2009

You might want to check ebay and other used books for a Helm factory service manual for your Bonneville. Helm does the authorized manuals. Helminc.com has them available new. It sounds like you might get your use out of it troubleshooting.

You said your car was the automatic temperature control... because you said you couldn't see the readout. I didn't check the manual unit.

Odd the passenger door module wouldn't have power. Do the windows and power locks work on that door?

cmazeo · October 2009

No, the power lock or window doesnt work. The window was stuck in the down position and I ended up powering up the motor in order to get it to go up. Will be checking on that service manual though.. thanks.

cmazeo · October 2009

Ok I screwed up. I thought I was using the ground post checking for battery on the fuses but actually I was using a positive post near the fuse panel. I rechecked the fuses the correct way with the car running and not running. Fuse # 33 and # 30 had no power car running or not. I traced # 33 and found the wire (brown) was spliced into 2 other brown leads. I tied a hot lead to the other brown leads and started the car. The hvac unit works fine. The blower motor has a loud hum and weak air flow but at least I am getting close to fixing the problem. Thanks !!!! again for your help... Checked on ebay for manual... I'll be buying one from there. Thanks again.

imidazol97 · October 2009

>Ok I screwed up.
Welcome to the club. At least you didn't "break" anything being backwards. I tend to break things that weren't already a problem.

This is what the factory service manual looks like and it is two manuals. This one is the Helm manhal.

try searching for combinations of factory, service, bonneville, pontiac, and see if you come up with some that aren't completely labeled.

Helm manual for GM

Try searching for combinations of factory, service, bonneville, pontiac, and see if you come up with some that aren't completely labeled.

here's one under 2000 bonneville service manual (no word factory) and it's $5 current bid 20 hours to go and $15 shipping.

link title

here's one for $9.99 and 9.99 shipping bid current.
link title

Make sure both manuals are there.

I didn't look under Pontaic without the bonneville word...

As for the circuits, I think studying the manuals will help.

Check the cabin air filter intake for the blower motor. If there's a filter it may be stopped up. See if the blades for the fan rotate freely while you have the filter out (you can easily see the blades when you're servicing the cabin filter out on the firewall.

cmazeo · October 2009

I ordered a set of service manuals from ebay today.... cost about $ 27 with shipping. Should be here in a few days. Thanks again for the help. Will let you know how everything turns out. There are a few things wrong with the car .. so this should help.

rockoh · October 2009

Ralph,

Man, you gave me the whole breakdown. Thanks dude, and I will let you know how it works out. I have been kind of busy so I just got a chance to look at the website again, but I am glad I did. I'll get back to you after my investigation.

Rockoh

shannion7577 · October 2009

I own a 1997 Bonneville - it heats the inside at start up - couple of minutes later - it turns on the air - two mechanics are left shaking their head - while saying I have never seen it do this before, have you - what was the cause?

popsydoodle · December 2009

I own a 1997 Bonneville. My heating does not work correctly since I had a total loss of power. I had removed the battery to charge it then put it back in. Since this happened I had a technician test the battery and charging system, both tested okay. He said the loss of power was caused by a badly corrodid battery terminal which he replaced. The control is temp controlled and when I set it for heat it just blows cold air. Some times shutting the vehicle off and restarting it corrects the problem. The other thing I have noticed is the Temp indicator flashes 2 to 3 minutes then stays on solid, this happens every time the car is started. Is there something that needs reset to correct this problem or is this an indication of some kind of component failure? The technician could not find anything about the flashing temp indicator and suggested I take the vehicle to a dealer for service.

imidazol97 · December 2009

My guess from a distance is that when you disconnected the battery, you did not turn off the AC unit first by turning the key ON and then shutting off the AC with the off button.

You might try moving the temp all the way cold for a minute and then put it all the way hot for a minute and see if it's able to recalibrate itself.

Otherwise you may have a cracked actuator gear. The actuator is a little electric motor that moves a lever that is the temperature blend door inside the heater box. If the gear is cracked, it slips on the axle. Therefore the programmer box doesn't know that the arm isn't moving even though the electric motor thinks it is moving it.

You may take off the plastic panel above the passenger's legs. Take off the glovebox door by removing screws along the bottom hinge. Then watch the white plastic arm sticking out of the heater box connected to the actuator motor on top of the heater case.

On Pontiacs those actuators are supposed to be difficult to get to the two screws holding it on.

There may also be an actuator moving an arm on the bottom of the HVAC case that is from an actuator that's inside the programmer box. Does your car have separate controls for passenger and driver temperatures?

popsydoodle · December 2009

I do not have seperate controls for driver and passenger, just the main control on the dashboard above the radio. I didn't know that you need to shut off the AC before removing the battery. I will try the recalibration first and let you know if that works? Thank you for your response to my problem.

Pontiac Bonneville Heating/Cooling Problems

Comments

Helpful Tools

Most popular vehicles