esseight

Hi all. Getting some mechanical issues sorted prior to the summer; one of my problem areas is the alternator to starter wiring harness. The insulation has fallen off at one end, and is likely to come apart in other places as well given the age and exposure to heat over time. I now have bare wire showing, and while it's not shorting right now it's only a matter of time before it could.

As with more and more of our parts, the wiring harness (P/N 944 607 029 04 I believe) is NLA so I'm looking for alternatives short of making a new one. The harness for the tiptronic model (P/N 944 607 029 08) is still showing as available, however. There must be some difference given the two different part numbers but does anyone have actual experience with these harnesses to comment? I read an old post that mentioned the tip harness was slightly shorter and may not work in a manual car, but it didn't seem like that was ever confirmed.

Thanks in advance!

chudson

Esseight - here's what I've been doing.

This harness contains 3 wires - power from starter solenoid terminal to alternator, the small blue wire from the alternator to the instrument cluster and the excitor wire for the starter solenoid. Yes this is a problematic harness and if the insulation delaminates and allows the power wire and the excitor wire to contact, the car will have a bad day. The starter will engage and run uncontrollably until the battery is discharged. This can also cause the harness to overheat and catch fire.

The harness is not too difficult to remove, but I have a garage with lifts and I've never removed one with the vehicle jacked up on the ground. The excitor wire and wire to cluster have a quick disconnect right behind the brake booster which simplifies the removal and the repair and the terminals are not difficult to remove from the white harness connector once the lock tabs on the terminals are bent down.

The small blue wire never seems to have a problem. I remove the sheath that covers the harness and then flake off (or cut off) the failing insulation. I then insure that the wire strands are still tight (and they can't unwind in the harness so they should be) and then I cover the bare wire with long one-piece shrink wrap (black for the power wire; red for the excitor wire), shrink the wrap with a heat gun and reinstall the original sheath. A stiff fish wire to pull the harness into the sheath is required. Again, I've never had to reinsulate the blue wire.

The area where the excitor wire "Ts" off of the harness has to be insulated with electrical tape and I suggest it be wrapped tight even though it can't contact the power wire once its new shrink wrap is installed.

I hope this helps. IMHO it's reasonable since Porsche no longer supplies a new harness and the Ice Shark harness (I think that's correct) are also NLA. Sorry I don't have pics. I took some but they aren't stored in my computer. Happy to answer questions.

Cliff

LTCMontana

Have you tried on of the dismantlers like DC Auto?
http://www.dcauto.com/

chudson

LTC - there is no problem purchasing a used harness, the problem is that they are all over 20 years old and almost everyone you find has failing insulation. It is occurring to my nicest / lowest mileage car and all of my 5 have experienced the same issue. Once you bend and contort the harness to remove it, the issue becomes worse. IMHO opinion, if you already own a harness with failing insulation, there's no need to purchase another unless you desire to reinsulate one on the bench and swap it for the one on the vehicle thus reducing the time that the car is disabled.

Cliff

jsheiry

There is no doubt this is a problem with these cars and as Chudson said above getting a "good" used one will probably have the same issue at some level. Once I left home and the 968 was in driveway in 1st gear, parking brake medium applied....Got back an hour later and car was pressed up against the plastic recycling bin and garbage can against my wooden gate. Gate was leaning 10 degrees. Only person home was my 12 year old son and I thought for sure he had started car and shoved into cans and panicked. After serious discussions & water boarding child services hauled me away....just kidding. After he swore 300 times he had not done it I finally believed him. After some more looking and an interesting alarm/horn issue I discovered the harness in question above had deteriorated and the starter would engage and jump the car forward until the battery or "plastic trash cans" gave out. I fixed as Chudson suggests with shrink wrap etc... When you get looking at this you will be shocked to find the heavy wire never really even had true insulation around it....it had some clear plastic covering but not a true battery style cable wrap "tough". Im sure there is a good reason for this but just add this to your "while your in there" list cuz it will happen. I think I promoted the problem a little with an engine washing and clean up the day before where some moisture had found its way down the harness by the next day and magically moved the car 12-14 ft up my driveway. I hated to think if I had left it in reverse it may have been sitting in my neighbors yard. I should have taken a picture of the spectacle but when I pulled into the driveway that was the last thing on my mind. Luckily there was no damage to the car.

LTCMontana

Thanks for the info. I guess I have something else to go look at tonight. Never had any issues with mine. It has lived in a pretty cool climate in a heated garage most of it's life so I haven't experienced the bad connector issues many others have had.

sm

esseight

Cliff - thanks for the write-up. Looks like that will be the way I go. Really have no interest in finding a used one - as has been mentioned even if it looks to be good now it's highly likely to have similar issues sooner rather than later.

My original hope was that the harness for the tip cars - which has a different part number and is still available - would work. I'm not sure why there would be a difference between the two, the wiring still needs to run between the starter solenoid/alternator/cluster/etc, but thought maybe it had to do with length if there were more/less bits and pieces to snake around between the two cars. It's an $80 part so I may give it a shot anyway.

Yogii

Is there any way to be proactive with the alternator to starter wiring harness? Would try to apply Plasti Dip, or something similar, help?

-Y

chudson

I've yet to hold a Tip harness in my hand so I really don't know, but it would be interesting to research. If it were an identical harness and only slightly longer, I suspect it could be used. Does anyone here have a Tip harness (off a car) to measure and/or compare?

That's what my write-up is about - being proactive. Disassembling the harness and replacing the insulation before the disaster occurs. There is a product called liquid electrical tape, but it would be difficult to spread it and get it to cure (in a controlled fashion) over the entire harness as would be any liquid product.

MLB968

Hi, ive heard the tip harness is almost too short. I made a new one from scratch last year, it wasnt a hard job after all . Old original harness inner sheath was completely crackled and crumbly. These things are a big problem waiting to happen. If you have an original harness in your car be afraid, be very afraid.
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