Wiring issue after painting

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bergcc
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Wiring issue after painting

Post by bergcc » Sat Feb 02, 2019 9:16 am

My 69 2000 came back from the body shop looking great with a new coat of paint and lots of flaws removed; however, I have the following observations:

1) When I went to start the car, I notice nearly all of the fuses were burnt out and little or no electrical worked. In fact, I was surprised the car started.
2) When I replaced the fuses, one of the tail lights was very dim (likely short).
3) Once I got the car home, noticed some smoke and smell of burning coming rising from behind the glove box. I quickly turned off the car.

I had some rust in the left rear wheel well, and am sure they did lots of repair work back there. I believe it's also where the wiring harness runs. My brother-in-law said a common problem is that folks doing the body work throw a torch on metal and don't think about what's behind it.

I know I need to start looking for shorts; however, where should I start? Secondly, at what point do you throw up your hands and buy a new wiring harness and just fix it once and for all?

My first inclination was the following: 1) check the harness behind the wheel well (I haven't done this yet cuz it's damn cold out) and 2) work from the rear tail lights forward looking for shorts. I haven't looked for shorts before, but am willing to learn since it's going to take time.

-ccb
69-70 311 in Pittsburgh

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notoptoy
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Re: Wiring issue after painting

Post by notoptoy » Sat Feb 02, 2019 9:25 am

First I would disconnnect the battery and check all your ground’s and clean them up where they attach to the frame/body. The easy ones are the large ones near the battery then there are lots around a car. Also a quick visual inspection just to see if there are burnt melted or visibly broken wires wherever you can easily see them. Smoking behind the glove box sounds like the fuse box itself could be a problem, pull it loose and look at the back see if there’s any burnt or loose connections etc. Next I would pull all the fuses, reattach the battery and insert one at a time and see what blows. You may be able to limit it to one circuit. Then trace down that circuit.
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Curtis
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Re: Wiring issue after painting

Post by Curtis » Sat Feb 02, 2019 11:01 am

I would start with the rear harness at the left wheel well. It runs right behind where they did the work on the outside of the frame. It then enters the body right there on the side.
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bergcc
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Re: Wiring issue after painting

Post by bergcc » Sun Feb 03, 2019 8:13 am

Thanks Curtis and notoptoy. I forgot to mention that the fuse box had been melted once before and someone bi-passed one of the fuses already. I have a spare fuse box (which is good because they are like $400) but have not had time to install it. The cause of the meltdown could still be lurking. As for the new wiring harness, I guess I have a lot to go one without taking the nuclear option.
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C.Costine
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Re: Wiring issue after painting

Post by C.Costine » Sun Feb 03, 2019 9:04 am

CCB, in order to get at and thoroughly inspect the harness behind the wheel you will need to get under there so hopefully you have a jack and jack stands. While there may be an autobody hack somewhere who starts his job by making it much tougher with a torch there is probably no shop anywhere that does this. Fuses can be blown by a short circuit as opposed to a current over draw, so it is possible that the ground in that harness was caused to come in HARD contact with one or more of the positive conductors, or a positive conductor could have come into HARD contact with a ground but it would be difficult too make this happen if you were trying to. I would look first behind the fuse box. Heat and smoke are almost always caused by a loose connection. Heat from one poor connection will often cause damage to the insulation of adjacent wires. Damaged insulation can cause other wires to make contact casing more heat, and more insulation damage enabling the current to take the "short" circuit to ground.

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Curtis
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Re: Wiring issue after painting

Post by Curtis » Sun Feb 03, 2019 11:40 am

I would say at this point with the fuse box history I would start inspecting from front to back and especially under the dash.
69-70 fusebox.pdf
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