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

 

some one please help i cant drive at night

 

i would check for a pinched or broken wire. could of happened when you reinstalled your bed. i am by far an expert but i would try that first then possibly check your switch with a good multi-meter