No Heat

[turbojoe89]

I have a 1997 Bonneville SSEI 3.8 Supercharged. Car runs great. Not many problems . . . . except I have no heat. Blower blows cold air even when the auto temp control is at 90 degrees.

Any suggestions?

[FormulaLT1]

Heater core needs to be replaced.

[Hypsi87]

Originally Posted by FormulaLT1

Heater core needs to be replaced.

or the mixing valve that controls the flow of coolant to the core

[randman1]

Originally Posted by Hypsi87

or the mixing valve that controls the flow of coolant to the core

My thoughts too. The air mix actuator controls the amount of heated air that has passed through the heater core as it mixes with outside air instead of the amount of coolant that goes through the core itself, but you have the right idea. Does the temp display blink for a minute or so when you start the car or after adjusting the temp from min to max or vice versa?

[bilmcc]

Originally Posted by randman1

My thoughts too. The air mix actuator controls the amount of heated air that has passed through the heater core as it mixes with outside air instead of the amount of coolant that goes through the core itself, but you have the right idea. Does the temp display blink for a minute or so when you start the car or after adjusting the temp from min to max or vice versa?

Hey.....

I have the no heat issue (and am taking heat from my wife about it) and my external temperature BLINKS about 30 times. What does the flashing mean?


I am not getting any A/C either.... I am hearing smething under the hood click and "turn on" (compressor?) when I press the A/C button on the dash controls. Could be another issue but thought I'd give more info than not enough.

[randman1]

Sounds like another air mix actuator. With a little work, you can verify the problem. First remove the glove box liner (black fuzzy part) by removing the 6~7 7mm screws.





Grab a flashlight and look in the left hole in the black steel dash structure. You should see something similar to the second pic. The silver threaded rod attaches to actuator and moves the air mix door lever (yellowish plastic piece). Start with the temp setting on full hot. Press and hold the temp down (cooler) to full cold while observing the movement of the air mix door lever. Then press and hold temp up (warmer) while observing the movement. The assembly should have about a 90* swing and move smoothly without stopping while adjusting from full hot to full cold and back again. If yours does not behave like this, or doesn't move at all, then the actuator is faulty.

[bilmcc]

Thanks for the speedy reply, I saw another one of your posts with the dash all apart and the great pictures as well.

I saw in another post that the actuator may need re-calibrated (by the dealer?). Is this a possibility if it is moving the 90 degrees?


PS: What function does the metal covering the arm serve?

[randman1]

The actual failure code description is "air mix motor circuit open, shorted, or needs calibration". This means that the wire could be cut, shorted to ground, disconnected rod, or faulty actuator. It's not 100% certain that your actuator is shot but is the most likely possibility. The nylon gears become flattened and can no longer adjust the arm.

Since the repair can be difficult and time consuming for a DIY'er or expensive if the dealer does the work, it might be beneficial to have the error codes read first. If you have a 93 or older Bonneville, the error codes can be displayed right on the ECC head. 94 and later need to make the trip to the dealer.

If you are referring to the black steel member that you have to look through to see what's going on, that is a part of the dash assembly. There's no cover to protect the moving parts of the actuator or air mix door. My 90 does have a piece metal that covers the works. There's a substantial amount more wires right in that area and I guess the engineers felt protection was necessary.