Chrysler Repair: 1994 Chrysler LHS Heat/AC controler, 1994 chrysler lhs, chrysler lhs

Question
I own a 1994 Chrysler LHS. I have a digital control, Auto heater/ac control. My problem is that it goes off and on on its own. Example if I have the temp set at 72 degrees it will display that on the control panel and everything is fine. Then just like that it all goes blank and the defroster comes on and the blower is at about its third setting and it blows hot. This may last for an hour or a week and then all of a sudden it will start to work again. Help we are roasting!

Answer
Hi Dan,
The automatic temp control system could either have a power supply issue or a computer control system issue. The "computer" is a part of that control panel in the dash. Before concluding a new panel is needed a test should be done to see if the computer has recognized any problems and described them in the form of two digit fault codes stored in its memory. 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).*
Because the head unit doesn't respond at all sometimes, I suggest that you check fuse #6 under the dash. It might have a subtle crack in its inner wire rather than being frankly blown. Such a crack can cause an intermittent function of the fuse.
There is also a 12V supply line to the a/c control that is directly connected to the battery on a black/pink small diameter wire attached to the + post clamp. So I would suggest that you examine that wire and make sure that it is not corroded or loosely attached to the eyelet which holds it to the battery clamp. Try shaking the wire gently while you have the AC "on" to see if that affects the readout.
Roland
*The code numbers range from 23-36. You can also get a decoder list at www.allpar.com/fix/codes_climate.html
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