Unknown Hot Wire in Van

newcampervan · September 2020

Hi, I recently bought a used Chevy Express van from the early 00's. I have not yet installed any of my own electrical. I was taking out some of the ceiling paneling so that I could put in insulation, and I noticed there's a pair of wires coming up from the dash, one black and one red. The black one has been cut, and the copper strands are exposed at the end. The red one goes all the way to the back, up through the ceiling, to some old piece of equipment on the roof that must've been an antenna or something like that.

When I touch the black wire to the vehicle chassis, it sparks. So then I took a multimeter and confirmed there are 12v flowing through the black wire.

The old antenna or whatever it was there's clearly no need for anymore (nor would it work anyway) so I just want to handle this situation as safely as possible as I am in the process of converting the van to live in it. However, the black wire goes down into all of the vehicle's electrical wiring and so it's not really possible for me to find it at the source and disconnect it.

Is it safe to simply cover the copper end of the wire in a bunch of electrical tape, and then essentially leave it up there, hidden behind my future insulation and paneling? Or are there other precautions/steps I should take to handle this as safely as possible?

BB. · September 2020

You are between a rock and a hard place... Yes, cutting the end of the wire and folding/using electrical tape is a start. If the run was not done carefully/correctly, you could end up with a short back to your instrument cluster--Which could disable the van down the road.

The color of the wiring may or may not mean anything, using a voltmeter or test lamp to see what wires are hot is a start. If may have to do things like test the wires with the ignition off and on, perhaps even pull the parking lights on, to figure out if the wire is "switched or not". And you don't know, the red wire may be hot (at times--such as when the ignition or lights are on too...).

If you were on the side of the road--Just insulating the wire for a short term fix is fine.

Given that you are redoing the insides of the van... tracing down the hot wires and where they originate and disconnecting from the power source is good practice--I have been stung too many times by intermittent shorts/opens. Addressing the issue now may just be better than later (as I am just debugging a possible short in my old pickup wiring/transmission circuits--Just hate intermittent failures).

-Bill

mcgivor · September 2020

Removing the wires would be the best solution particularly if they appear to be inconsistent with the vehicle wiring as they may be part of a deleted after market system. Often installers use insulation displacement tap connectors to piggyback an ignition switched, or not switched wire in the loom, this can lead to intermittent problems as those connectors often cut the strands of the host wire, sometimes cutting it entirely.

To establish which circuit it is connected to what I've used is a piezo buzzer connected to the suspect wire, then remove each fuse until it silences then refer to a wiring diagram, or you could simply follow it back to where it is being powered.

mike95490 · September 2020

When you tape it up, use RED tape, so you might have a chance to think about if it's Hot ( when you are digging around in the wires 2 years from now )

InCogKneeToe · September 2020

newcampervan said:

When I touch the black wire to the vehicle chassis, it sparks. So then I took a multimeter and confirmed there are 12v flowing through the black wire.

The Black Wire Sparks/Arcs, suggests to me that the "Load" is still in the Circuit. Like a CHMSL. (center high mount stop light.)

Unknown Hot Wire in Van

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