tangram

First, a disclaimer - I'm not too mechanically inclined so explanations need to be simple! I'm in need of some help. Yesterday I had the wiring harness of my '95 C2 replaced. After driving it home, relatively hard, I heard a fan kick in when after I'd parked the car. No problems, happens often, as it should.

This morning, I backed the car out of the garage to wash it (beautiful day here after a very long winter). After turning off the car, I hear another fan noise. That's odd, all I did was pull it out of the garage and the engine is stone cold. Well, that was half an hour ago and the fan is still cycling on and off. My suspicion is that this electrical gremlin (which is draining the battery as we speak) was caused by the wiring harness replacement, which was done by one of the two authorized Porsche dealers in Toronto.

I would like to have a bit of info on what fan this is so I can inform the dealer. It is blowing air out of two rectangular openings on the underside of the car, directly beneath the engine compartment. I can not see a fan running; I can only hear it. Can anybody give me some insight into this? Thanks.

tom_993

The quick answer is “take it back to the dealer.”

The long answer: That fan shouldn’t be running under these conditions. That fan serves two purposes. One, forced air for the cabin heaters (you don’t have your cabin fan on high with the cabin temp up high, do you?), and two, engine cooling. It’s when it’s cooling the engine that the air will come out those two openings you describe (when it’s heating the cabin, those openings will close so that the hot air goes into the cabin). The engine shouldn’t be hot, so it shouldn’t need cooling. See the quick answer above.

Tom
’95 993

tangram

Tom, thanks for the info. It's going back to the dealer tomorrow in morning. I took the car out for a drive this evening, and when I turned the engine off, the fan kept cycling on and off (I stopped counting after 10 times) for around 15 minutes). This was not after a hard drive - previously the fan would not have even run after such a drive.

I have a feeling that the dealer is going to feed me a line such as "I can't see how changing the harness could have caused this problem". If anybody can offer some insight into this (after all, they had to mess around and remove a bunch of stuff to replace the harness), I'd appreciate it.

tangram

Well, the dealer at first thought the problem was a bad relay but popping a new one in didn't apparently help. They traced the problem back to the climate control unit (CCU) and said that they could fix the problem for C$2,000 plus a half hour of labor. Good grief.

Here's where things get interesting. The problem (blower fan staying on too long after turning ignition off) only occurs if the cabin temp is apparently set at 21 degrees C or higher. But, on returning home with the car, I specifically cranked the temp up to max and the fan speed up to max before powering down. To my surprise, the problem has magically rectified itself.

This leads me to believe that yes, the CCU was indeed faulty but was not in of itself the source of the problem. Perhaps replacing that relay did in fact do the trick. Odds are the problem will pop up again but who knows.

One last thing. The dealer refused to acknowledge that replacing the wiring harness had anything to do with the problem. Suffice it to say, now the warranty work is complete, I will be heading back to my local guys at Mantis Racing in Oakville, Ontario.

ApexL8

Tangram,
If this is the unit you need, here is a new one on eBay for $900:

<a href="http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2411822086&category=6765" target="_blank">CCU on eBay</a>

I hate intermittent faults, they are the hardest to troubleshoot.

Don Magee

Just as an additional data point, right BEFORE I pulled into the dealer lot to have my harness replaced, I had the engine compartment cooling fan come on and stay on continiuosly. It was a 20 buck sensor in the engine compartment.

tom_993

Used CCU's can also be obtained from various used sources, such as LA Porsche Dismantlers (www.911pcar.com) (no affialiation) and other used vendors listed in the magazines.

Tom
'95 993