Tail light fuse keeps going out

[ajfriz]

The tail light fuse burned up last night taking out the dash lights. As soon as a new fuse is put in, it burns it up too. So far I've disconnected all of the plugs from the tail light housing, disconnected the dimmer switch, checked the tail light relay, checked all of the wiring to the tail lights, and replaced the front parking light bulbs and it still shows a direct short on the tail light fuse when I check it with an ohm meter. What else should I check? The truck is starting to look like a complete wreck now that I have the dash torn out and all the lights off This is on a 89 truck BTW.

 

[Combat Chuck]

I'd look at the wire loom itself, sounds like you may have a frayed or fried wire.

 

[pappy]

Have you isolated the taillight harness? I seem to recall a plug that runs to the back of the truck. If you disconnect that, and the fuse still pops you need to be looking forward. If it doesn't pop, then your short is isolated to the rear.

 

[ajfriz]

Yeah I've checked the entire harness to the tail/parking lights and it looks brand new. The truck itself is in amazing shape with only 90k miles and it hasn't ever been wheeled. Very confusing. I've completely torn the dash apart and disconnected about every plug there is and I still get a direct short.

 

[2ndGenToyotaFan]

I seem to recall a plug under the passenger seat that had all the tail light stuff going through it. Have a look there.

If nothing obvious shows up, I'd just cut the Hot wire that's grounded so you can test up stream and down stream, and move and cut again till you have it narrowed down...

 

[GRM]

I seem to recall a plug under the passenger seat that had all the tail light stuff going through it. Have a look there.

If nothing obvious shows up, I'd just cut the Hot wire that's grounded so you can test up stream and down stream, and move and cut again till you have it narrowed down...

x2. That connector acts up often. I've had it blow that fuse on 2 trucks.

If thats it, go to the local CAT dealer and grab a deutsch replacement.