Lebaron 89 TII ATC not working

[MiKe]

Hi

I have problem with my Lebaron 89 ATC system. It blows only hot air and switching between automatic and manual control does no difference. Air flaps works normally so i quess vacuum leak is not the problem?

I tried to study Haynes last night but i did not get any answer from there. I got the impression from the book that there is no heater valve but only some kind of flap that controls flow through heater core. Is this true?

Any suggestion what to check first?

-Mike

[NAJ]

The ATC has self diagnostics, my info is from a 1990 FSM so see if it works on your vehicle.
To start the test depress the Auto, Floor and Defrost buttons at the same time,after each fault code is recorded depress the Panel button to resume the test cycle.
At the end of the test cycle the display will return to the setting before the test was started.

[MiKe]

Thank you for your help!

I tried the self diagnostics of my ATC unit and it worked just like you said.
I got only one code: 02. Do you know what it means?

-Mike

[NAJ]

Code 02 is a Blend Air Door malfunction.
The info I am giving you for 1990 ATC so hopefully it is the same as yours since this is all I have.
The Blend Air Door Actuator is located on the A/C-heater housing above the floor hump to the right of the accelerator pedal.

[MiKe]

Thanks for the added info!

I removed Blend air door actuator and did testing according posted instructions. Seems like i have faulty motor in the actuator. I opened the actuator and removed motor from the gearing then I did the diagnostic test of ATC again. Motor receives about 5 volts but it will not spin until I help it with my fingers. Does anybody know should motor get more voltage from the ATC unit?

[NAJ]

If step 4 is the voltage test it is 4 volts at 85 degrees.

[MiKe]

I did not think that one all the way. Of course max voltage is no greater than 4.0 volts!

I opened actuator motor and noticed that coil brushes are worn out.
I bought new identical DC motor from local electrical parts suply and will try to fix actuator by only swapping the motors.

[85lebaront2]

If that doesn't work, I think I have an extra blend door actuator. The semi-automatic 87, and the full-automatic later ones seem to have the same actuator and housing mounted module. The only oddball is the Imperial with a full electronic system (no vacuum) even that one seems to use the same blend actuator.

[Oklahoma Wolf]

Quote:

Originally Posted by 85lebaront2 The only oddball is the Imperial with a full electronic system (no vacuum) even that one seems to use the same blend actuator.

Imperial, Fifth Avenue, Dynasty, and New Yorker above 1991 had the full electronic. I do believe the blend door servo is still the same though... it was electric throughout the whole range of years.

I was going to suggest making sure the blend door isn't getting stuck on something inside the air box, but it looks like it's indeed the blend door motor at fault. I'm having similar issues on one of my two '88 New Yorkers I should really get busy and take care of. It works, it's just really slow to move the blend door.