my gauge lights don't work but my heater, 4x4, dummie, and Hurst shifter lights do... but when i turn the dimmer up to get those ones on the gas gauge stops working on either tank (goes to just past empty).

and my turn single and high beam indicator lights don't work either... it a 81-86 model truck (its suppose to have 4 headlights but someone put a 75 front clip on it with 2 lights), 4x4, short box, thats suppose to have a/c - but someone hacked it out, and twin tanks. if any more info on the the truck is needed please post and i will put it up. otherwise please help!!! like i said I'm lost.