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Thread: Crispy wires and much more!

  1. #1
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    Default Crispy wires and much more!

    Hi Everyone,

    I have not posted in a couple of years because I have been without a Noble. A friend of mine purchased an M12 a couple of years ago and has run into some of the typical problems. The previous owner of his Noble did a small number of the required fixes but it appears he did not do anything related to the electrical system.

    Not long ago his Noble experienced the 10G wire from the alternator melting and catching fire. The wire burned both at the alternator and unfortunately up behind the two AC lines inside the loom. We cut apart all of the melted insulation and repaired a the two red wires in the loom that run up to the main fuse. Our plan is to get the car running as stock then do the recommended 4G rewire upgrade. I have a couple of questions.

    1. Inside the melted loom we discovered a brown wire. It is taped off in the photo below, but we have no idea where it went. My guess is that it was spliced into one of the two red wires in the loom. Does anyone know?


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    2. As part of this repair of wiring we attempted to determine if there was a draw on the battery. We removed the negative battery terminal connection and used a test light between the battery and the ground. No matter which fuses we pulled we were never able to eliminate the drain on the battery. The question is does the built in trickle charger have to be disconnected in addition to the alarm system fuse being pulled to verify if we have a short? Also, could the alternator have been damaged and causing a short in the system? If not, my plan is to go back through the wiring loom and look for more melted wires. We get a completed circuit even if we pull the main 80amp use in the engine bay.

    3. It appears that his previous owner did not upgrade the front axles or replace the axle nuts on the rear axles. Who sells these these days?

    Thanks for all of the advice... Nice to read old post on this forum!

    Ed Cohen

  2. #2
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    Wow crickets.... People on this forum used to respond within seconds! Where do people send questions these days if not here?

  3. #3
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    sorry ecohen2 but do not recognize the wires

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    Nice to see you on the forum again Ed.

    Sure sounds like a short. Don't have an answer, but check the alternator to see if it has a short. That would be my first guess, assuming that referring to the red wire between alternator and battery (i.e., that charges the battery). A quick check would be to see if your test light still glows after disconnecting alternator wires, especially the 10G red wire.

    I vaguely recall reading that some of the early M12s had undersized wiring in that area.

    Haven't heard of a built-in trickle charger unless it's an add-on.

    I don't recognize the brown wire, but it's been a few years since I worked on my alternator wiring harness. Section 8 of the Install Manual lists wires and their colors. Most of the browns go to earth/ground. A DVM in ohms or continuity mode would tell you if that's where your mystery wire goes, or if it connects to one of the reds.

    Hope this helps.
    2007 M400, NUS 206

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    I forgot to address the axle nuts. Try a Porsche parts dealer -- P/N 999 084 641 01.

    For front axles, you might check Rossion and Turbo Hoses. Am guessing from Willy's reply that he doesn't stock them. I tried Rossion, but their store is down for maintenance tonight. Re. front axle bolts: personally I haven't found the need for them. Have been to the track quite a few times and have about 14k miles on my car. Have never experienced a loose front axle. I check them before every track event. One of our Forum's prevalent service and parts providers told me that he's never seen an original front axle fail, but that was a few years ago. But I fully recognize that a lot of owners sware by them.
    2007 M400, NUS 206

  6. #6
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    I got ahold of a wiring diagram and you were correct the Brown wire is always Ground / Earth so that is fixed. The heat melted the rest of the wire, but it was connected to the frame about 2 inches below that photo. All that was left was a connector..

    Thank you for the part numbers!! I will pass them onto the owner and get those right away. The owner has LOTS of play in one of the front axles... He is headed out of town, but something clearly has failed. I figured just to be safe we would replace those axles... I will try to reach out to Willy and see if he still has / makes them...

    Thanks Bill!

    Ed

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    I do stock the upgraded / track axles and have some in stock and another batch in process

    Good luck with Rossion they get them from me

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