Drive Guys: Electrical issues often a puzzle

Local,Ed Kriston,Jeffrey Boone

Dear Ed & Jeff:

I have a ’96 Toyota T-100 pickup truck that’s right now parked in my driveway with the battery cables disconnected.

For some unexplained reason the parking lights come on by themselves and run the battery down. The first time it happened was about a year ago in the middle of the night during a heavy rain storm (my neighbor called to alert us).

The battery was jump started, lights went off, and it was OK until recently.

My wife called me at work to say one side of the parking lights were on. She disconnected the battery. I later reconnected it and the lights were off.

The other night all four parking lights came on. The light switch on the stalk is off.

I turned it on and off, jiggled and tapped it as well as tapped fuse box compartments to no effect. The last incidents happened in dry weather. The truck is a four cylinder with 132,000 miles and runs well otherwise. Any ideas? I’d like to fix it myself if possible.

Jeff W.

Hi Jeff,

I have no doubt that you have a serious electrical concern here. My guess is that there are wires in a connector that are corroded to the point that it is causing this intermittent.

I suggest a shop that is good with electrical concerns to tackle this one. Also one that has access to a manufacturer’s wiring diagram for your truck. Electrical work is never easy and not every technician out there will want this one in their bay.

My forte, when I worked on cars, was electrical repair.

One thing that might help the repair tech: When this happens, pull fuses one at a time to see if the lights go out. This will help diagnose the problem when it is happening. This is something that the tech may not have in his favor. Good luck with this one.

Jeff: Hi Jeff — I agree with Ed. This can become a time-consuming issue. The advice about the fuses is always a good starting point. You need to isolate the actual system supplying the power to the lights.

Once this is done you can then start tracing wires to find the shorted/crossed wires. This could be in a connector — as Ed said — or even where two wires rub against each other.

Like Ed, I used to spend a lot of time performing electrical repairs that no one else wanted. I didn’t get rich doing it, but I liked the challenges.

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