rvermilye

The A/C on my 94 964 has been giving problems over the past years. Refrigerant recharge every spring has helped, but about a year ago my temp. regulation on the CCU has gone bad. When not using A/C, if I put the dial on the blue setting I get cool air. If I move it just a bit off the blue dot setting I immediately get max heat....there is no regulation as I move the dial to hotter temps. If I turn on the A/C, it will blow cold air if the dial is on the blue dot...moving it off the blue dot at all gives max heat. Just had refrigerant put in and when driving the A/C is nice and cold, but about every five minutes I get a blast of hot air come through the vents. This just lasts for about 10-15 seconds and then it goes back to cold air. I noticed when sitting at idle, the compressor seemed to kick in and out occasionally. Suspecting the CCU unit is bad. Has anyone replaced the whole CCU unit..and if so, what was the cost of a replacement unit. Can they be repaired? Would like to get this resolved once and for all.

milutintin

I suggest you diagnose the problem. I dont think you will solve it only by replacing the CCU. There are lots of thing that can go bad.

Start by reading this:

http://privat.bluezone.no/toreb2000/ccurepair.html

altarchsa

I have the EXACT same problem.

altarchsa

I can tell you that a while back, before this problem, I purchased a used "non-working" CCU, just because it was a good price for a spare, and I have tried all combinations of exchanging entire unit, face with electronic board, just the board, and the body of the units with no effect on this problem. Makes me think it has to be a problem with modulation by the servos, but I can't figure out what would make them act in unison other than the CCU. ??????????????

rvermilye

I'm going to have them run the diagnostics again on the A/C when I get a chance. Hopefully it can pinpoint what the actual problem is.

Rocket Rob

Can the CCU be repaired? Yes. I've had mine repaired by Loren (http://www.systemsc.com/products.htm). He was very responsive and the CCU worked perfectly. He has some good FAQ troubleshooting steps on his site. Try those first.

No affiliations.

campoj2

What did he charge you for the repair?

Rocket Rob

I don't have the receipt with me at work so I'm going on memory but my guess is $350-500 range. Much cheaper than buying a new CCU. But check with Loren for his latest prices. He's a member on RL too.

Laker

+1

if you have access to a Scantool, it would be best to check for faults and review the TSB.
Apparently Porsche Dealers were also too anxious to replace the CCU

I have them uploaded on this post

my guess is a bad temp. sensor

Rocket Rob

Laker - If you want to link to a specific post in a thread, copy the URL and add number sign and the post number (ie URL#274). See sample below

https://rennlist.com/forums/964-foru...ed-19.html#274