Electrical Gremlin

[Delkra]

Hey all... I have an 85 C10 that has never had any electrical problems ... until today.

I was working on vacuuming and cleaning my truck today. I had the door open for an extended period and I know that the overhead light at the back of the cab gets very hot when the door is open too long. No problem, I'll do what I have done in the past and pull the bulb. Unfortunately, I used a metal screwdriver to pull the bulb and pop it shorted to ground. I checked and the underdash light was still working.

But then I noticed that my stock clock (which was working just seconds before) had stopped. I broke out my test light and plugged it into the cigarette lighter, but it wouldn't work. The lighter has always worked in the past. I put the overhead bulb back in - no light, door open or closed - so I pulled the bulb back out. I then put a test meter on it and I am seeing 4.5 volts across the terminals at the overhead light when the door is CLOSED and ZERO volts when the door is open.

Here's where it got very odd: I realized that my test light turned on when I closed the door with the bulb in the overhead light. Even though the overhead light doesn't turn on - if it is there, the test light works when the door is closed.

I have never seen something happen like this before. Is there a wiring diagram out there that will show the courtesy light circuit? Does anyone know if the clock is part of the courtesy circuit or is it shorting to a different circuit???

How do I even begin to troubleshoot this? Remember - everything was working up until that little POP when my screwdriver shorted one side of the light to the lamp assembly mounting screw!!!

Any ideas or help appreciated!

Thanks in advance!
-Delkra

 

[foamypirate]

Silly question, but did you replace the fuse? Clock and overhead light are on the same circuit.

 

[Delkra]

Silly question, but did you replace the fuse? Clock and overhead light are on the same circuit.

Not a silly question, but yes... I checked the TL/CTSY fuse.

Hmm... Does the clock and overhead light circuit get power from the fuse marked TL/CTSY? I thought that is "Tail light / Courtesy Lights" so I checked that one figuring it meant the interior cab lights. If they do, then yeah, that fuse is ok. The under dash courtesy light is still coming on and off when the door opens and closes.

That's the only fuse I checked, though . So if the clock and overhead light are on a different fuse, I just need to figure out which one.

 

[Boone83K10]

or you could just systematically pull each fuse and look at it.

 

[austinado16]

This is really no big deal. You've simply popped a fuse. Look at the fuse that powers the horn and cig lighter, it's blown.