Alrighty! So when I first bought my truck, the driver side low beam didn't work. I adjusted my grounds, and then the low beam worked but the high beam no longer worked. I just installed the headlight relay and now my low beam doesn't work but my high beam does.... Any thoughts??


Update: My instrument cluster lights just quit working any help with that would me much appreciated

Update two: The instrument lights turn on, BUT! they don't turn on when you pull the switch back to gauge lights, or headlights. They'll only stay on if you set the switch half way between gauge lights and OFF

 

I would say it's a bad switch, do the turn signals work, 4 ways etc?

 

89-90 uses a separate switch for the headlight dimmer IIRC. That would be a good place to start for your headlight problems. Instrument lights go through the headlight switch.
Do you have any water leaking in around the windshield?

 

Last night there were two brown wires coming from the same loom as the headlight wiring that were just hanging in the inner fender. I pulled them out and touched them against the ground, they arced, and no more gauge lights. My blinkers work, and the blinker lights and the high beans light works in the dash, just not the rest of the lights

Edit: no there are no water leaks around my windshield

 

Hey Cougar!!,think the 2 brn., wires 209's found are his park/ clearance/ signal lit., wires????


whosdunit.

 

Hmmmm..... 30 amp fuse labeled ext lmp is blown... Hmm....

 

According to the wiring diagrams there are 2 tan wires that merge into 1 and goes to the left turn signal and marker light.
That "ext lmp" fuse #4 (supposed to be a 20 amp) is hot from the battery and feeds the headlight switch for running lights and the instrument lights through fuse #14 (3 amp).

The reason I asked about the leak is I've seen water drip on electrical switches and fuse boxes before causing interesting problems.

 

Fuse fixed the instrument lights, just need to figure out the driver side low beam

EDIT: Replaced headlights and now everything works. Thanks for the help guys.