A few days ago, I was driving to work in the rain and my dash lights went out. Yesterday, I worked late (after dark) and had somebody flash their headlights at me on the interstate. I realized at that point my tail lights were also out. I did some searching, learned that dash and tail lights are on a common circuit, and pulled my headlight switch to do some testing. I replaced the switch and that did not fix it. I replaced the fuse under the dash (fuse 17) and that didn't fix it either. I tried checking various circuits with a jumper and a multimeter, but I'm not really sure I have the right diagram or that I'm doing things properly, because I thought I was jumpering the headlight circuit (headlights are functional using the switch) and I couldn't even get the headlights to light up using the jumper. (jumpered B1-H on the pigtail diagram). BTW all the wires in the pigtail seem to be intact and undamaged.


I read in a few other threads it could be that the radio is shorting with the dash light circuit. I have an aftermarket radio that the PO installed and the power is a wire stuffed into the radio fuse (11) that gets voltage when the key is turned on. I would not be surprised if there is a short. However, the radio seems to work perfectly fine. Would the short be at the headlight switch or at the radio? The wiring at the switch doesn't appear damaged or frayed.


As you can probably tell just from reading this, wiring is NOT my strong suit. Please speak slowly and use lots of pictures. I may break down and take it to a stereo shop, but I am tired of not being able to do my own electrical repairs (this truck needs a lot of them!)

 

Just a thought and could not help at all but a few years ago my dads trucks lost it's running lights got home one night (89 chevy/ I know I've tried to convert him) and it turned out to be the trailer plug wiring had corroded and grounded out the wires. Put a new one on and she was good to go. And come to think of it the 95 trans am i had lost the dash lights due to someones wiring of a aftermarket radio, i went and bought the correct adapter and they started working again. Just food for thought but I don't know if it'll help you

 

Was the parking light fuse blown? If so, did it blow again after replacing it?

 

Fuse was not blown. I did notice that the PO was using a 20 amp fuse where it calls for 10 or 15. Might be that he was having issues. I got the right diagram for the headlight switch and was able to jumper various circuits - headlights worked, dash circuit did not. I am going to check power to the fuse when I get home. If the fuse isn't getting power, what should I do next? What would cause that - fried wire behind the fuse box?

 

When you jumpered the appropriate terminals, did the parking lights work?

 

I'll have to check when I get home. What would that tell me?

 

Ok, so i traced the issue back to the fact that there is no voltage to the fuse. Due to the fact that this happened in the rain, and I don't have the weatherstripping on my hood, I'm guessing there is a short near the harness that plugs into the firewall. What wires (colors?) should I start with?

By the way, I took the trailer harness out of the equation so that's definitely ruled out.

 

Parking lights do not work.

 

Are you checking the parking light fuse or the dash light fuse.

 

Well this is embarrassing....I was not getting power to the #17 fuse, so I pulled the dash apart enough to trace the wiring. It turns out that if the #4 fuse is blown (which it was) then the #17 fuse does not get power. Both fuses are listed as dash lighting....somehow overlooked it. I was surprised because I used an "add-a-fuse" to the #17 spot to illuminate some after market gauges which also went out, so I did not think to check all the other fuses.


On a positive note, I am learning quite a bit about wiring and am getting more comfortable with it.


When I bought the truck, I had never even laid hands on a carburetor. Since then, I've rebuilt the engine, fixed a handful of other wiring issues, replaced most of the interior and learned how to do bodywork. Not bad.....


I still hate wiring, but now I have enough confidence to try and get my fuel gauge working.