'89 temperature controller
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 30
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From: Metter Georgia
'89 temperature controller
My '89 convertible digital temperature controller will move the air mix door to the cool side but not to the hot side. Apparently there is a loose connection in the controller, it will respond sometimes when the car hits a bump or rounds a curve. Are there repairs or schematics to repair the digital controllers? Any help would be appreciated.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Programmer - a postcard size device above and to the right of the accelerator - sends the electrical signals to the motor that moves the Temp Door. There should be a Tech Tip on how to take it apart and resolder the Board, though it could be a Control Panel issue. I'd start by disconnecting and reconnecting the battery. Then with the key on, select Auto. The Programmer should cycle the Door (and nothing else should work) so that Control Panel can learn it's position. Once that's done, everything should work, but if it doesn't, you can check voltages at the motor. It's power and ground leads are Tan/Black and Yellow. In one direction - Warm - there should be 6 to 12 volts on one of the wires and the other wire should have 0. In the other direction - Cool - the voltage should switch. If it does, the motor is bad, though you can also apply an external voltage and ground to verify that the motor isn't working. Otherwise, if there's only voltage in one direction, it's usually the Programmer. Of course if you have the correct voltages and the door isn't moving but the motor is running, it's the linkage between the motor and the door. It's connected with a plastic clip and that clip often breaks.
Le Mans Master
Joined: Jul 2001
Posts: 8,183
Likes: 3
From: Santa Maria, CA
Yeah man, if you determine it is te controller, remove the hush panel from the driver side(the one that is above your shins when you sit in the driver's seat).
Look toward the back, mounted on the firewall is a black plastic box.
It is behind the brake pedal and next to the steering column.
It'll be a bear to get out, but once you do, inside will be this:
You can re-solder the joints using the resistors again, or replace them.
My pic's caption is a little misleading....the resistors were not burned out.
Just the solder was loose, but I decided to replace the resistors with new ones of the approximate same value.
Let us know if it is the clips that broke. Here are pics of both:
(this one you will not be able to see because the entire dash has been removed in the pic)
circled in yellow.
To see it, you have to do this:
(remove the blower module, not split the case. Do not split the case.)
and try to look down inside.
Look toward the back, mounted on the firewall is a black plastic box.
It is behind the brake pedal and next to the steering column.
It'll be a bear to get out, but once you do, inside will be this:
You can re-solder the joints using the resistors again, or replace them.
My pic's caption is a little misleading....the resistors were not burned out.
Just the solder was loose, but I decided to replace the resistors with new ones of the approximate same value.
Let us know if it is the clips that broke. Here are pics of both:
(this one you will not be able to see because the entire dash has been removed in the pic)
circled in yellow.
To see it, you have to do this:
(remove the blower module, not split the case. Do not split the case.)
and try to look down inside.
Last edited by pablocruise; Jan 29, 2008 at 09:13 PM.
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 30
Likes: 0
From: Metter Georgia
Thanks Sun CR and 89 Paul, this info is very helpful. I spent money at the Chevrolet dealer and still didn't get what I needed to solve the problem. I will take this thread and correct my heating problem.
