My girlfriend just got a 1989 250, and I was putting in a radio and speakers in it, because it didn't have either when we bought it. Well the wiring for the radio was all hacked up. Well while wiring up the radio, I touched a wire that was hot to a ground(it was stripped back, AWESOME). The wire color was black with a yellow tracer. I had the truck running with the heat on (it was cold out), and once I accidently grounded that wire, poof the gauge cluster lights go out. I also discovered that the parking lights no longer work. On the front or rear. The headlights work, brake lights work, turn signals work, but no parking or gauge lights. I checked all the fuses under the dash, and of course none were popped. And the wiring going into the back of the fuse block were fine. Anyone have any ideas?
Thanks,
Tommy

 

Could it be a fusible link.

 

Horn work? Can't be a fusible link because all the lighting runs off the same one.

 

I don't know if the horn works or not, haven't tried it. But yes all the other lights work like I said. I will check the fusible links in the morning in the daylight. On a side note, I pulled the dash cluster, radio, heater controls and all the other stuff bolted to the dash, and I didn't see any wires burnt, or any wiring modifications (besides the hacked up radio wiring). I will also check the headlight switch tomorrow also. They were working perfectly fine until I accidentally grounded out that wire Any other ideas or anything to check in the morning?
Thanks,
Tommy

 

Double check the fuse. Sometimes it will burn near the blades and it can be hard to see. Test it with a test light or ohm meter.

 

Tested all the fuses with a test light. All are good.
Thanks,
Tommy

 

Black with yellow tracer comes from the R terminal of the light switch. Draws power from fuse number 8 and/or 14. Check those fuses again please. Might want to remove them for a visual check before doing the light switch. One of them should be blown. If they are good then back probe at the light switch on the power wires. You should have power on the pink w/red tracer and the tan wire. Hope this helps.

 

One more thing. Fuse 14 is at the top of the fuse block, right below the horn relay. It should be a 3 amp fuse. If I remember right, it is easy to miss it when crawling under the dash. It is in the portion of the block that only has 2 fuses side by side.