I have a 92 chevy Silverado 4x4 and have been having major problems with my taillights! every time I turn my head lights on my running lights, turn signals, and brake lights wont work. ive looked for shorts or bad spots in my wiring loom cant see anything. I replaced my head light switch, turn signal switch, and tail light circuit boards hoping to fix the problem. the weird thing is I have some magnetic towing lights that plug into my 4 pin connector and they work!!! Is driving me crazy and would appreciate any help possible or ideas to try. also checked fuses and relays in truck and seem good. it will blink once in the dash then stop I think the head lights are drawing all the juice away from a bad connection somewhere but not sure at all.