QuestionI have a question. I have a 1994 Chrysler LHS. The A/C does not function on this car. It acts like the blend door is stuck in the heat position. Is there a common problem with any particular component on this car? Such as the ATC Module in the dash, or the blend door motor? Or perhaps the blend door itself? Also, how do you run the ATC Diagnostics on this vehicle? Is it accessible with an aftermarket Scan tool ( OTC GENYSIS, updated to 2003..I know, need to update it further...can't afford it right now). Please advise. I am quite familiar with A/C systems and doing troubleshooting..just don't have any manuals or information on this system....
AnswerHi Robert,
The Chrysler DRB II scan tool is one way to readout the codes. But the unit does have some self-diagnostic capability, but not as detailed as with the DRB. The engine has to be running and the car not in motion to do the test. Simultaneously press the floor, mix, and defrost buttons, (the 1st,2nd and 4th on the top row) and see if the display unit begins to blink. Release the buttons when it has started to do that and then after it blinks for a while longer watch for two digit numbers to appear on the readout. Those are the fault codes. If the first number appears and stays in place, push on the first button in the bottom row (panel) to continue the readout. At the end of the readout the unit will return to normal settings.
Then write back with the number(s).*
If the head unit doesn't respond at all, then check fuse #6 under the dash. There is also a 12V supply line to the control that is directly connected to the battery on a black/pink wire on the green plug on the rear of the control unit that should be checked to verify that you are getting that power to the control unit.
It may be a part in the air distribution system itself rather than the computer that is the problem. And you also might find a working used unit at a wrecking yard.
I have not heard of any particular part being a cause of problems with the the unit. The blend door actuator is on the bottom of the unit, above the tunnel, and can be exchanged without removing the unit from the vehicle. Then you can move the blend door by hand to see if it is binding.
I have the '94 shop manual and will be pleased to copy the pages about servicing it at 9 cents per page and mail it to you. When you receive it you can send me back unused stamps to cover the copying and postage.
Roland
*You can also get the code translations at www.allpar.com/fix/codes_climate
The blend door feedback error code is 23, the blend door stall failure is 32.
