JayW

1991 C2 Tip Cab 37K. My air conditioning was mostly blowing hot air but once in a while cold. The car is at the dealer now - diagnosis is a bad temperature sensor in a/c control unit (aka climate control head). Repair quote is $1700 (gag) for the climate control unit plus $220 labor. I told the dealer I would call back on Monday. Has anyone had this failure before and if so has anyone had any luck replacing just the sensor? If not is there a decent source for overhauled or R&R service for the climate control unit for less than $1700??

dfinnegan

You can get the unit repaired . . . sorry, can't recall who, but a search should turn them up, or someone will chime in.

Marc Shaw

You could look on eBay - they turn up there on occasion.

Marc

dfinnegan

Try Systems Consulting

Heirsh

When i suspected I had a bad head unit (I did not actually) I sent the unit to Otto's.

http://www.ottosvenice.com/

He charged me very little to confirm it was working. He shipped it in the same nice packaging I sent it to him in. I wholeheartedly recommend him for this work. There are also many others that can do it. How many people will tell you the unit is fine when you think its broke? Perfect opportunity to stick me, but he didn't.

YYC930

WOW !!!! Am I lucky that I found this thread.......just had this problem on a 993 in my inventory......$2,300 CAD for the part !!! WTF !!!.......the dealer's diagnostic computer confirmed that the fan speed switch was not working properly.........gonna send it out for repair next week.

Thanks for the leads guys !!!

Marc Shaw

There is one on eBay at the moment here (no affiliation)

Marc

Toddimus

If they it's a bad interior temperature sensor, then maybe it's just that the little thermistor behind the little grill on the face of the control unit is covered in lint and grime like mine was. Maybe just get a bit of "canned air" or a gentle blast from a compressed air hose into that grill. I don't think that would really hurt anything, and it just might work.

I also had one of my flapper valve servo motors go out that made the heat and cold act strangely. I had to go one tick above full cold to get true full cold. That was a while ago, so I'm not exactly sure of the symptoms, but I do remember the fix. I took out the servo motor re-soldered some terminals and cleaned up the resistor track inside the servo itself.

Now...I just got done fixing another problem with the system, battery drain due to that little fan running all the time pulling air across the very same interior temperature sensor.

If I could just get my AC system leak checked and refilled, I'd be "chillin"

Colin 90 C2

I have a spare that I bought a few years back, but have not needed to use it. PM me if interested.
Colin

911addict

Porsche do a price based on trade in old unit. New is £1000, swap is £500.
(assuming we are talking about the control unit in the cabin/dash).
BTW they are different units for left and right hand drive.

JayW

Thanks for all the tips!! I think I'll pay the dealer for the diagnosis and decline the $2000 repair. BTW, after the shock wore off I pulled my copy of Adrian Streather's book out. After a little study I found that he says there is a repair kit for the a/c control unit temperature sensor part no. 964 618 943 00. (AND a blower sensor repair kit part no. 964 659 148 00.) See p. 366. The Dealer service rep. denied the sensor could be replaced when I talked to him. Anyone had any luck with these Porshe repair kits.

Eric Kessel

I had a similar issue with my 90 C2. When it was cold out it would frequently go "nutty", and no matter what settings I had, it would blow hot at full fan speed. Got hot quick. It turned out to be a bad wire in the ribbon cable that goes from the face plate (which holds the temp sensor) to the contol board. After that was soldered up, it's been fine since.