MMartini

Hi,

I have problems with the heating.... or it get hot or you are freezing.... I removed the CCU unit to have a look and noticed the little fan is missing!
Could this be the cause of the erratic heating and does anybody know if these fans are sold?
Thanks, Marco.

DaveK

It could well be the reason for the erratic heating, since I think it blows the air over the temp. sensor.

I believe you can buy the fan - I'm sure mine was replaced the first time I had work done on my car after I bought it. I'm afraid I don't have more details though.

JasonAndreas

The replacement fan is Porsche part no #964-659-148-00 (MSRP $183.59) and yes it could be the source of your problem. Also be aware that the PO may have removed the fan because of a problem with a transistor on the CCU main PCB causing the fan to run all the time which will drain the battery in a matter of days. The temperature fluctuations could also be from failing temperature chamber servo motors. Their operation becomes erratic before they fail outright.

DaveK

My word - how did Porsche possibly become such a profitable car manufacturer.....

MMartini

Thanks for the help, it must be the fan as all the servo motors are working fine..... another $200...pfff

Alex Sol

I am in the same boat or worse. My mechanic has just informed me that I need a new ccu at a cost of about $2000.00 canadian dollars. or about... $1700.00 u.s. dollars. Anyone have that they won't be need for about 10 years?

springer3

If you can, send me your old one. I have zero experinece on the 964 CCU, but plenty with a similar Mercedes unit from early 300 E. The problems are usually a failed transistor, and easy to fix.

Be sure to check every component connected to the CCU. Sometimes a failed fan motor or actuator is what damages the CCU, and the new one will smoke upon power up. As with most of these types of comments, don't ask how I know...

Eric Kessel

If you get brave enough to open it up, check the continuity of the temperature sensor in the CCU. Mine had a faulty connection, and when it was cold out, the CCU would only put out full heat, until it felt like working correctly....... fixed that and it's been fine for a couple years........

Lorenfb

The CCU in both the 964 and 993 is very reliable and rarely if ever fails.
Most mis-diagnose climate control problems and assume it's the CCU,
when the real problem results from the external elements, e.g. actuators,
sensors, & relays.

Most should avoid repair shops' recommendation for a CCU replacement without
a proper system evaluation with the Hammer or a PST2 tester. Most shops aren't
much better at diagnosing climate control problems either.

For DIY CCU repairs, care must be used as the microprocessor within the unit can
be easily damaged. Many CCUs can be damaged because ground wires are not properly
connected in the engine compartment when engine work is performed.

Alex Sol

Dam, I'm not sure what to do now. I have gotten a price of half of what the local Porsche dealer is asking / extorting (1100.00 Canadian or $950.00 USD) but no point if that is not the problem. When calling the local Porsche parts dismantler, he mentioned that the CCU is often the first part to be sold. Likely because it's mis diagnosed... Can I take the CCU down to Jack @ GTek (no affiliation) the ex-Porsche Dealer mechanic who has gone on his own for 15 years to have it checked? Because it's been pulled out, can it be checked on the hammer?


Springer 3, thanks for the offer to check my CCU. I am in Canada and can send that unit down but I think i'd better check the other components first. Where to start. I have searched the other threads about the fan blower motor as it appears to be a major headache.

Eric, I have an electronics expert in the family. He has fixed my broken T.V.s by finding a 7 cent fuse or resistor by carefully checking. He has also made a card for Satelitte T.V. from buying a few parts from the local electronics store. But I digress..


So far, I've pulled off the hood, removed the gas tank, moved the entire front console/ fuse box forward and underneath the A/C lines and into the middle of the front trunk then bench tested the fan blower motors (crude hook up of battery to fan motor directly with only a few sparks flying!!), cleaned all connectors and am trying to find the fan's resistor or resistors (which i believe there is only one at the rear that runs the rear blower motor?).

I don't have a shop manual and am going by my mechanic (a bit of a hack and not that knowledgeable on 911s) who has the software and basic manuals for 'all' cars. I am starting to regret not taking it to Jack in the first place but my mech and I are learning and enjoying the work (sort of).

Please help..... and thanks a lot!

Alex Sol

springer 3, I have a 1994 e320 wagon 7 seater... the CCU on this car has a mind of its own also but works for now.

Alex Sol

Loren, it looks like you work on these types of problems at your work or is your work unrelated?

Should we look to replace the actuators, relays and sensors then?

Is the servo the actuator that you are referring to?

JasonAndreas

Alex,
What are the symptoms of your CCU?

Lorenfb

"Alex,
What are the symptoms of your CCU?"

Jason has the right approach. Just "step back" and gather/provide the basic info before
making assumptions on what's bad.

Alex Sol

Yes I am a total novice at this and my mechanic has lots of experience as BMW Dealer mechanic but not much if any with Porsche.

Symptoms - the previous owner had put 30 am fuses (and kept a half dozen in the front trunk) for sticking into th 25 amp fuse slot. I was not interested in continuing this practice. With the car off, if you would change the burnt fuse, you'd get a flash and bam, the fuse would get blown. That's with the car off.

So, after searching through the many threads and the info is very detailed, I figured let's pull it apart and check the fans and resistors. Out came the fuse box in the front trunk and the entire console. We removed the gas tank and a bunch of the interior ie: glove box etc.

The fans bench tested okay and it was determined that the CCU was 'acting' up and getting into the speed 3 and 4. We pulled out the CCU, 'banged' it a few times and cleaned contacts. Now we are getting to the CCU symptom. It will work in speeds 1, 2, 3 and 4 but not all the time. That's the reason my mechanic thinks we should replace. In case it fails again, it would be a pain to remove everything again and costly -not to mention a fair bit of labour charges (- right now he is pretty reasonable with me as we've been working on my previous vehicles and loves this Porsche - 95 Integra, 00 Oddyessy, 90 Jeep Cheroke, 94 MB e320, 93 Pathfinder)

Symptoms wise, what sort of answer would you expect?

Regards, Alex