2000 986S electrics

[Gilles]

Anser,

I had a similar issue with my '07 987CS, not sure if your car has the same electrical box, but drove me nuts until accidentally found the culprit.

It was the No. 4 (positive cable from the battery to the distribution box), where it connects to the distribution box at the firewall, it's fairly easy to check.

PS: No. 11 is inside the cabin, behind the glove box, but the connector side is on the front trunk..

[Anser]

Thanks Gilles.
Checked it and the nut was tight. Still has the factory paint stripe on it.
Your idea lead me to look at the high current distribution box.
Thinking a loose connection could cause a surge.
I asked if she hit a bump when it happened, and she did.


I went to move it to have more room, and now it blows the fuse immediately.


Ideas?

[blue62]

Sounds like you need to test the wiring harness for a short with a volt meter.
If you have the Bentley service manual there is a description on how to locate a short on pg. 97-39.

[Anser]

That is the plan.
I do have a better feeling about finding the cause now that is a solid failure!

[blue62]

Originally Posted by Anser

That is the plan.
I do have a better feeling about finding the cause now that is a solid failure!

Yes a solid failure is a positive, chasing intermittent failures can be very frustrating.

[Anser]

Short from load side of fuse B8 to gnd.
Seem to be in the harness that feeds the relay box in the trunk. I was able to create or fix the short by pushing the harness close to the relays.
Pulled the relay box out and it never shorted. Was even able to fire the car up without the fuse popping.
Got as far as unwrapping and inspecting the wires, but nothing definitive yet.
It's in dare somewhere........

[Anser]

Found it! Since nothing was found in relay harness, I unwrapped the harness next to it.
Just one little section of the wire that carries the power for DME was exposed between the cloth wrap.