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

I'm having a problem when I turn on the heat, the radiator fan turns on even
when the engine is cold and stays on continuously. I also realize that if I
turn on the air conditionor, and turn the temp way down, the compressor clutch
doesn't engage anymore. Very strange. I did the self diagnostic test with the
heating control and it gives a 36 error. Communication problem of some sort.
Anyone have a glue what to do? HELP!!!!

 

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:
http://www.4s.com/fourseasons/tech_...h/AB337_Tech_Tip_Transducer_Quick_Test_01.pdf
It's an easy method of testing with a battery.

Steve m...

Ronda

 

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