susanrsa

Apologies for yet another posting regarding 964 climate control but after going over what seem like dozens of threads and hundreds of posts, I still have questions and haven’t seen anything that quite resembles my current ‘issue’.
Both the Porsche dealer and my local Porsche mechanic have said it’s the CCU but obviously I want to be sure before I splash out for a rebuild. Shops seem to be more interested in quick costly parts replacement than diagnosis.
The unit has worked at times, but currently I have no blower action at all. This happened last Spring, according to my Porsche mechanic, he “cleaned the contacts on the unit”, I had A/C through the summer and then the fan stopped again.
- A/C system had full recharge last year
- CCU powers up, the A/C button light comes on.
- Hot or cold air will come through the vents, so that would seem to indicate the servos are working correctly?
No fan, at any temperature setting, hot of cold.
Blower fuses have been checked are fine.

Ideas?
Thanks

Rocket Rob

First of all, welcome to Rennlist. It sounds like you may have one or more faulty servors. Try following this troubleshooting procedure. You should also pick up a copy of Adrian's 964 book.

Porsche 911
Enthusiast's Companion™
Carrera 2, Carrera 4 and Turbo 1989 – 1994
by Adrian Streather

Lastly, you may want to become a formal member of Rennlist too. We also appreciate when people post pictures of their cars.

groovzilla

"ROCKETROB"...don't mean to stray off topic here but i always appreciate your insight and help regarding issues that crop up...

was wondering if you have oil leaks on the 220K mile motor in your 1990?...or have you had the top end done and leaks sealed??

elbeee964

First off, Rocket's engine (like a Chuck Norris Fact) would never simply "leak".
Instead it chooses what oil isn't up to the job -- and ejects it. With power.

Such spots are called, 'potholes'.

Rocket Rob

William,

Thanks for the kind words. Have I had my cab's engine apart? No. Just the usual scheduled maintenance (oil changes, valve adjustments, etc). Does it have any leaks? Yes but they are very minor, 2-3 drops the size of quarters per week. The engine still pulls strong and runs smoothly. I know, eventually, I will need to drop the engine and do a rebuild but not yet.

I do think its funny. About 10 years ago, I had a Porsche dealer tell me that I needed a total engine reseal to fix a few drips. When I asked for the cost, they estimated $11K plus parts. I laughed, saying, do you know how many quarts of Mobil 1 I can buy with that? They assured me that it was the right thing to do, quoting it was a safety issue. At the time, I was paying mechanics to do all of the maintenance. Coincidentally, I switched mechanics and they found that my oil pressure sensor was leaking. A few hundred dollars later, I had a dry car again. I think of this story, every time someone asks if I have any leaks. The engine has added another 100K miles on it and its fine. Most leaks are minor, once you find them. I think mechanics tend to recommend rebuilds to quickly. The present leak appears to be coming from one of the cam chain covers. I am living with it for now, while I sort out my new coupe.

The bottom line is - take care of your engine and it will run for a long time.

I hope this helps.

Rocket Rob

susanrsa

Well, I sort of managed an avatar, will look up something better.

I do have Adrian Streather's book, will have another look tonight.

So, the servos .......... looking at the info I've gleened so far, the servos operate the vents and temperature control, and fresh air circulation, all of which seem to work. My problem is the blowers, or lack of action from .........

Rocket Rob

Sorry, I didn't read your post very well. Do you have access to a Hammer or ScanTool? It would be helpful to pull the CCU error codes. When you say the fan doesn't work, do you mean the fans in the dash or the rear blower in the engine compartment? I'm thinking you mean the fans in the dash. If you press the defrost button, do the fans run?

When was the last time the fans and heater/AC worked properly? Was there any changes or repairs done to the car around that time?

I'm sure together we will find the problem.

susanrsa

No worries. I don't have access to a Hammer. Yes dash fans. I understand that the rear blower is for the heat function, I'm going to check the rear fuse for that and the connection when I get home. No air moves currently.

The blowers worked for the trip to Squaw Valley last summer to check out the 356 West Coast Holiday, died sometime after that. No work on the car in that time frame.

Frustrating ................

Rocket Rob

Here's another reference for you. Its a list of all of the TSBs (technical service bulletins) for the 964. See #46 under Interior. http://www.pcarworkshop.com/index.ph...C_Parts_Guides

MONBUTEST

First of all control the fuse in the rear lid fuse box on the left,
then try to put 12 V at the wires of the rear fan blower (easy to unswitch).
If your hear horrible squeeky noises...or nothing, change the aluminium bearings probably used, by bronze ones

wellcraft290

just an idea I had one car PPI and they said I needed to replace the resistor for the fans if this went and there was an update on this that the fans would not work. Just an idea.

TA911-64

I don't know if this helps....I have an'86 that had a/c no fan blowing. Turned out to be the a/c relay. $7.00 at local auto parts. Plugged in....instant a/c.