Taillight gremlins
 

Man I hope someone on here can help me. I bought a 2003 4x4 last week it had lamp out and brake lights on in the dash seller said headlight out and e brake needs adjusted. Changed headlights lamp out still on. Changed brake lights fixed lamp out light. Problem is when I turn on the park lights the brake lights come on and when I step on the brake pedal the park lights come on. I've unplugged everything I can think of brake switch taillight assemblies front park lights light switch trailer brake control trailer plug. I'm now lost anybody been through this? Maybe TIPM? Thanks for any help it's killing me having the new baby stuck in the driveway.

your trailer plug is the problem or bad ground on trailer plug
you got back feeding happening

I unplugged the trailer plug from the wiring harness didn't help. I've checked and cleaned every ground I can find. The brake light in the dash is on but the cruise still works so I'm guessing that must have something to do with it. The local dealer says first thing to try is reflash the tipm. Not sure about those guys never had to have someone else work on my stuff before.

About the only thing I can think of that I haven't tried is the underside of the fuse box where everything plugs in I'll check that soon as I get time.

Lord knows there's enough wires on the damn thing I coulda missed a few. I'll kick the kid outa my shop this weekend so I can roll around under it a little better. I believe the truck spent most if not all it's life in Portland Oregon. Really no rust or corrosion to speak of on the undercarriage. Thanks all for the help I'll update if when I get it figured out.

Figured it out. Previous owner unfactoried the factory 4 prong trailer plug wiring. Thanks again for the suggestions. I'm sure I'll come up with more stupid questions now that I can drive her.