Air conditioning

while I am driving with the air on, suddenly the heat will come on and I cannot turn it off, it will eventually turn itself off after a couple of minutes. Honestly the off button means squat

Is there any type of automatic feature with your climate control system? If you post the year I will look for TSB’s regarding known problems with the car. Searching for TSB’s is very high on my diagnostic stratagey list (you don’t want to spend time searching for a fault that has already been identified).

The car is a 1994 Chrysler LHS , it is my daughters car so I am not sure if it has a automatic climate control system .

The car is a 1994 Chrysler LHS , I am not sure if it has a automatic control system.
Please reply

There is a TSB for heater and blower speed changing by themselves. The problem is solved by BCM (Body Control Module) reprograming. The TSB also mentions that the Chrysler scan tool can be helpful with diagnosis.

Thank You So much

The problem may be in the “head unit”, which is a fancy name for the heating and air control panel. I have a 1994 and it started acting flaky. I purchased a used replacement from ebay for around $35 and installed it myself. This completely fixed the problem. Replacing this part is incredibly easy. Pry off the trim around it, remove some screws (I think there are four), and there is an electrical connector and a couple of wires that plug in. It took me less than 10 minutes. I’d try this first.

I don’t know if the Dealer can or will be able to re-program the BCM. Perhaps they will try to sell you one that is new and has the new program. I don’t see how a independant would have such obscure software,you are going to have to make some calls.

Further info. This is a exchange BCM repair not a reprograming
Old BCM has version 7.4
New BCM has version 7.5
Take this exchange action when the diagnostic/calibration procedure in the service manual does not fix problem
Group: Heating and AC
TSB number 24-17-93 Rev. b