hi everyone, i have a 94 LHS w/ATC blowing heat at all times. the controller will respond to thermostat change, but never blows cold. system is fully charged, compressor kicks on, fans kick on, just heat instead. is there a way to get the controller into diag. mode? if so how? what do you look for in responses?

 

This is for a 97 with ATC, but it should work, give it a try.
1. Engine running, car out of gear.
2. Set temp **** to 75 deg. (at this time don't worry about the actual temp).
3. Press & hold the floor, mix, and defrost buttons (3 of 4 top buttons excluding the AC).
4. When the display begins to blink, let go the buttons.
5. While blinking, the ATC is testing and calibrating.
6. If no problems are caught, the system will go back to 75 (that's why it was a chosen number), if any other # appears (23-36 are the fault code range on the 97 year model), it is a fault. Record any fault # and post, I will let you know what it is.

 

will do, thanks. i won't see the car again until sat. it's at another residence where i can work on it on weekends until i get everything up and running good. then i'll start driving it. i appreciate the help.

 

finally did the test, got code 36. after that, i disconnected the battery to clean the terminals, test drove the car. the a/c freezes me out now. also shows no codes. do i have a bad controller? what does 36 mean? thanks, jon

 

36= ATC head communication failure.

The test is also a cal on the system. It may have cleared up the problem. Disconnecting the battery will clear faults from memory. The com fault may have been in there for a while (a one time fail). I'd let it go and see what happens.

 

i'll let it go for now. i'll prolly pull out the controller and check the connection. if it happens again, i'll replace it for a rebuilt unit off ebay for $70 or so. thanks for the help, i do appreciate it.