96 Bonneville Temp Display Flashing, Need Help.

[pherse]

I have a 1996 Bonneville and have noticed that about 10 seconds after start-up the temp display starts flashing and I hear an odd noise from the passengers side foot well. It will only blow hot air, no cold or A.C. From what I have read it is the air mix door actuator. I need help locating this to fix it. Any and all help is appreciated.

[randman1]

I partially removed the dash as described in the factory service manual to replace mine. There has also been a couple of other posts that describe other methods. One method includes using a hole saw and cutting the steel dash supports and the other method is to remove the heater core door. Personally I wouldn't cut my dash in that manner and the other seems a little tricky but just might be worth a look.

The cut method was bumped recently and shouldn't be too hard to find. The heater core method might take some searching though.

93 was the last year the error codes could be displayed right on the ECC head. Since replacing the air mix door is such a PITA, you may want to consider taking the car to the dealer and having the codes read before digging into it.

[pherse]

I had the codes read and it cost me $100.00 It did have a code which referred to the air mix door operation. I removed the glove box compartment and with a little help from a screwdriver I was able to get the lever to complete its full swing and what do you know, I had cold air once again. Still trying to figure out the best way to get at that sucker.

[randman1]

Well that's your problem... you shouldn't be able to move the actuator arm by hand (or screwdriver in your case). The next time you adjust the temp, the HVAC programmer will notice the actuator isn't working properly and start the blinking again.

What you've done is good for a temp fix but you'll still need to replace it.

[pherse]

Does it bolt on from the top down or bottom up?

[randman1]

The actuator? It has two 7mm screws that insert from the top. Here's a closer pic. You can see the two vertical "stalks" where the screws thread into:



The arrows point to the 2 screws that secure the heater core door. This is the part that can be removed as one of the methods above. the PCM and HVAC programmer will have to be removed to gain access to the cover. The tricky part is to disconnect, reconnect and calibrate the rod. You'll need to get a screwdriver or two in that area through the glove box (just like you did to adjust) and let then be your fingers.

[pherse]

Does the heater core have to be removed, or is the actuator located on top of the box?
I really appreciate all of the help and the pictures are fantastic!

[randman1]

No need to remove the heater core, just the cover. I probably should have included this one above to show the mounting of the actuator. You can see that the actuator is screwed to the top of the cover only:

[pherse]

A final question before I attempt anything, Can the heater core box cover be removed without removing the dash?

[randman1]

Yes, so I understand. That's one of the other methods for actuator replacement. You need to remove the PCM and HVAC programmer in order to get some room in there. I've never tried it myself as the procedure came from another member but again, it's worth exploring. The upper 7mm cover screw looks like it might be tough to get at and you have to fiddle with the rod through the glove box.

[pherse]

I'll keep you informed on how I make out.
Thanks again.

[pherse]

Well I did it. Removed programmer and housing along with everything that was in the way in order to remove the heater core box cover. Took off the aix mix assembly and discovered that it had a cracked plastic gear. Replaced the air mix assembly with another from an auto wrecker, hooked everything back up and all is well once again.
Thanks again randman1 for all of the help especially the with the pictures. If I have any other problems that may arise I know where I turn for help.

[randman1]

I glad you corrected the problem. And thanks for posting your results. I expect to see many other similar posts once it becomes air conditioning weather and again in the late fall.

This is quite a time and agony saver versus removing the dash. Can you describe how you reconnected the rod? Difficulty? Problems adjusting?

[pherse]

Reconecting the rod was not as difficult as I thought it was going to be. On the right hand side I was able to get my hand and arm up on top of the heater core box cover where the actuator is located and grasp the rod with two fingers to line it up on the left side where it will snap down into place. In order to do that I steadied the rod with my right hand and with a long screwdriver in my left I was able to snap the rod into place. Adjusting was quite easy and I did that before connecting the rod. I set the climate control setting to cold A.C. and let to motor move the rod into place. I then closed the flapper door which allows hot air from the heater core in and snapped the rod into place.

[randman1]

Awesome. My heater core cover is cracked and I have a replacement sitting in the basement. I haven't had enough ambition to put it in yet but you have confirmed that it doesn't require dash removal.