I just had the same problem - turned out to be a short in my trailer
wiring harness. I 'thought' the fuses were good, but although it
looked good it was actually bad. I put another fuse in it's place and
saw a little flash when the new fuse blew. At first I suspected the
headlight switch or the multifunction switch in the column... turned
out it was neither.
My truck is a 1996, but the premise is the same. I disconnected the
headlight switch from it's connector. To isolate the problem I found
a connector at the back of my truck behind the bumper that goes to the
tail lights and disconnected it. I also found a connector under the
hood of the truck close to the ABS module/underhood fuse block that
goes to the front lights, and I disconnected that as well. Then when
I checked for shorts at the headlight switch connector and found
none. I plugged in a new fuse, and the headlight switch, then my dash
lights and warning buzzer were working. I plugged in the front
running light harness and they worked as well. With the problem
isolated to the rear lights/harness, I started looking for shorts and
found my trailer wiring harness to be the problem. I connected the
rear harness without the trailer wiring and everything was working
great. I threw that harness in the trash....
Don't discount the headlight switch though. I have had to replace the
multifunction switch in my truck twice in the past 6 months, so I
don't think a bad headlight switch would be out of the question. It's
tough to stomach the $$ the dealer wants for the electronic parts,
especially since they are non-returnable - so you cannot just buy a
new switch, try it out, and if that's not the problem then take it
back for a refund. If you are savvy with a 12 volt trouble light or a
multi-meter then you can save yourself some $$ by troubleshooting.
Hope this helps.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.