**HELP** wiring harness bad on 964???

[tmctguer]

a friend of mine owns a '93 964. a few days ago, he was driving and saw & smelled a bit of smoke coming from the air vents. he took the car to a small independent repair shop that has done quality P-car work for him in the past, although that work had been limited to oil changes & tune-ups.

the mechanic found a blown fuse -- no surprise here. then mechanic probed around with a VOM and diagnosed that there was more wiring damage. apparently, wires were showing 'hot' that should not have been and he concluded from this that burned insulation had cross-connected wires in bundles or in the wiring harness.

the mechanic concluded that the wiring harness needed to be replaced. he has not taken off the dashboard, and he has not been able to show my friend any substantial wiring damage.

the mechanic was able to talk my friend's insurance company into covering the repair cost as fire related damage (approx. $7K). so at this point, the repair work will be free.

the dilemma is whether a complete wiring harness is really needed, and whether to keep the car at the smaller shop as opposed to taking it to the big P-car dealer in the area.

questions for the board:

1). how can my friend be comfortable with the diagnosis? should he approve the mechanic to proceed, and have him call him to see the damage once the dashboard is removed?

2). should he keep the car with the small independent shop, or have that type of major electrical repair done only by the P-car dealer? after all, there is a big leap between doing oil changes and replacing a wiring harness.

3). should he insist on getting a second opinion of the repair, then decide where to have it done?

4). what is the likelihood that 1 burned wire could cause damage that would require the entire wiring harness to be replaced?

the small shop has time invested in the diagnosis, and has talked the insurance company into paying for the repairs. the reimbursement could be at risk if he changes the shop that will do the repairs. But the local P-car dealer seems like the safest place to get such a major repair done.

your opinions are appreciated.

[Kurt B]

Been there done that. It seems to me, the why is the problem. Something must have been connected bypassing a fuse and then, as time went on and it shorted, there was no way to relieve the energy except to burn the wires. An alarm install?

1 wire can do it if you don't catch it in time. The wires are all bound up, and even a clock wire (in my case) that went, burned a lot of other wires in the bundle. The wire itself ended up being bare copper with no insulation running through the middle of massive looms. The other wires lose their insulation, melted away around it, and eventually you have hot and ground lines naked adjacent to each other in the bundle. Nasty.
He has to know the why. Without the why, it could happen again even after a new loom, then what?
A quick disconnect in the battery would be nice. But it needs to be done by a guy who only does wiring.


In my case, the clock/interior/trunk light wiring bypassed the fuse. That's right, the top part of the fuse panel had the hot lines in, and the clock wire ran off of that instead of off on the bottom where the fuse was between the hot line and itself.
And the trunk light shorted out--seems common the way it's constructed. Should have been a simple blown fuse but it wound up melting the holy hell out of a mass if wiring. I had a lot of work running new wires and repairing everything, but the main concern is getting that wire so it's got a fuse between itself and the hotline. If it ever happens again in anyway, it'll blow the fuse not burn the loom.

[tmctguer]

Kurt B -- good observations. the only non-stock item is an aftermarket stereo. i also made the connection about 1 damaged wire causing a chain reaction.

he is still not sure which way to go with the repair of the damage -- stick with the small shop, or go with the local P-car dealer?

[Speedster94]

hallo
If there is only 1 Fuse blown , check that Circuit for Damage . The elektrics in a 964 are much more complex than in a 911 . To change the complete Harness the Car has to be taken widely apart . The Interieur,
the Gauges ,the Freshair Box , the Fueltank , The Top of the Engine ,etc.
This is Job for a Porsche knowing Person ONLY . If the Mechanik is not familiar with the 964 and up Models you will run into a Desaster . The Cost will be way above 7 K ,the Harness ( 4 pieces )and Fusebox alone will be about 6 K . I would estimate the Work at least 40 Hours ,and some small stuff you need to replace about 500 $ .
harald

[tmctguer]

the mechanic in question estimates 20 hours, an engine drop, and a dashboard removal. definitely a major project. hence the concern for having a small shop do the work.

[Speedster94]

And he will leave the Fusebox , Fresh-Air/AC -Box and Seats .
I dont know your Mechanic but to me it doesnt make sense . Most of the Wires run under your Carpets/Seats and under the Dashboard (
You can not remove in a 964 ,you can only pull the Gauges )
Good Luck ,harald

[Dez]

I'm having the same problem except i'm going to try and do the "repair" myself. I'm not looking forward to it to be honest but it needs done and i am broke. My 924 wouldn't start and the fuel pump wouldn't come on. I changed the relay but still no joy so i had a look at teh wiring beyond the fusebox and found at least 2 wires which had gotten so hot they were down to the copper. So i spent most of saturday pulling the entire front wiring harness through the bulkhead so i can try and trace these wires and replace them properly.

Can anyone give me any tips on how to do this and anything to watch out for?

Cheers.

[Dez]

I also forgeot to ask how can i find out what colour of wire comes out of a plug at the fusebox if the wire is bare?

Thanks..

[FRED/LI]

Hope it's not evidence of impending doom for us 964 owners but the 993s had the harnesses recalled in Nov last year. I happened to see a damaged one that was being replaced at the time. It was evidently deteriorated halfway along its length inside. The wires apeared to have had moisture trapped inside the outer covering. Some of these wires are fairly thin and the insulation/ covering is minimal. Once one gets a bit hot, the damage can be done to all its neighbors.
Hopefully your problem is localized.