ok i have 2 problems

#1. about 3 weeks ago i put a new fuel pump in my truck. the gas tank was full so dropping it was not lookin to fun so i took the bed off to get to the tank. i put the pump in and put the bed back on and now my tail lights are not working right...my brake lights work and my turn signals work but the left light does not work when im am just driving. my question is: is there a ground strap on the bed that could be effecting this or do i have another problem.

#2. a few months ago my fog lights, dash lights and tail lights desided to crap out (all at the same time.) i would have to find a "sweet spot" on the light switch to turn them on but i could not have head lights. so i would have to find that sweet spot and manualy hold my brights on to see and be seen at night...then one day it went away and was working fine....well now its doing it again

 

#1 - Are you sure that one of the filiments on the bulb are not burnt out? That would be my first guess. Than, since this happened while doing other maintenance, I would guess some wiring was compromised. To answer your question, I highly doubt there is a ground strap on the rear of the truck (there are no grounds in the rear of my '96, and the '01 service manual shows no rear ground either)

#2 - I would suspect a faulty headlamp switch.

 

the other option is you cut threw the wire housing while removing or install the bed back , and the bare wire could be grounding itself out on the bare metal

 

I would check for cracks that might have caused moisture/water to seep in that resulted to the malfunction since you did a pump replacement. Also, the circuit might have been interupted. Make sure you don't have a short or a blown fuse.

 

i agree that it is probably grounding itself due to being a bare wire.

 

Pretty much was said already. You either have a bad bulb(s), pinched a wire or have one shorted out.Usually they blow fuses if they short so check your grounds.

As for the headlights, its the switch. Replace it.