LHS Radiator fan comes on when I turn on heat??

I have a 94' LHS and it was doing that last year in the winter on and off. It never caused any problems and finally in the summer during a driving rainstorm the AC quit working. Well, after I diagnosed it down to the AC pressure xducr it turned out to be the culprit the whole time. Was a $75 part only available at Chrysler. Fixed the fan issues for good after replacement. I would imagine that yours is the same. The original part was made by GE the replacement was made by someone in Japan. They also changed the connector design and required some soldering skills and heat shrink tubing work. Not a big job really. As for the error 36. I have no idea what that is from. Sorry can't help there. The compressor clutch should not turn on at this time of year (unless the temp where you live is above 32 degrees F).

Steve m....

Hi Steve, thanks for replying. Could you tell me what a AC pressure reducer does? Where is it located? Is there a way I could test it? Sorry for all the questions but I don't know much about air conditioning systems. -Thanks Ronda

The AC pressure xdsr does exactly that. It monitors the pressure in the AC line and passes that info to the Body control module computer to decide how and when to run the fans for the radiator. It seems this sensor becomes flakey and causes the computer to think it needs to turn on the cooling fans for no reason at all. It's located on the passenger side of the radiator. There is a procedure to test it that I found on the web:

Steve, thank you so much for this info! I will give it a test as soon as I can. It makes sense because I was having some eratic behavior with the ac working and not working in the summer. I was guessing that the refrigerant was getting low. Now I'm thinking maybe the compressor wasn't kicking on when it should have. Then sometimes it was working fine. Now the compressor doesn't engage at all even in warmer weather. Now with the radiator fan coming on....something is wacky. The weird thing is that the radiator fan comes on the instant I press certain heat controlls. Front defrost is one, but if I then hit front vent the fan goes off. Strange. Maybe that sensor is screwing everything up so I will give it a go. Thanks again!

Or unless you turn on the defroster. Defroster turns the AC on by default - to dry the air being directed to the windscreen. At least it does on my New Yorker