First time poster here!

Have an 86 truck with a 22RE engine, and ever since putting on my Rebco box, my lights have been acting goofy. I'm pretty bad at electrical stuff but being a poor university student I don't really have the money to have someone fix it for me.

So here it goes:

When my headlights are OFF (key on or off), my brake lights will work fine. Radio works too, but only if brakes are applied - if no brake light, no radio.

When headlights are ON (key on or off), radio will be on all the time, running lights work, but brake lights don't.

Obviously somethings backwards, but I wouldn't really know where to start.

Thanks in advance for any suggestions!

 

Sounds like a grounding issue. Headlights work by connecting one or the other bulb filament to ground (via the headlight combo/dimmer switch):
- http://www.4crawler.com/4x4/CheapTri...l#HarnessTypes

Could be those affected circuits are finding ground through some place and tuening on the headlights kills that ground path. Main cab ground point is behind driver's side kick panel, screw into the sheet metal with a ton of brown ground wires running to it.