Not sure why it stays on when I turn off my truck and my reverse lights too if I have it in reverse and truck is off. I have to take the negative off battery. Some help please??

 

Did you ever figure this out? Everything that should work with the key in the run position works with the key off and removed. I unhooked all of the wires to the steering column, and the problem persisted. I bought an 87 last week from a friend, and two days ago the same thing happened to me. The first day I had it I took it to a car wash to clean up the engine, and everything was fine. The problem began a couple of days later after I drove it during a heavy, wet spring snow storm. I had not done anything to the electrical system, so I suspect something has shorted out. The truck has been driven day for the last two years with no problems. The battery ground wire is intact. Could this be a faulty diode in the alternator? Would that allow the current to flow back through the system? If so, can anyone tell me how to perform a diagnostic test? I have a digital multimeter, but I typically only use it on AC circuits. Thanks, and sorry for so many questions in my first post. The truck is a base model regular cab 4x4 with a stock 22R and about 203000 miles on the odometer.

Jim