I'm having a problem with my tail lights!

They are not working properlly when I turn on my fog lights and or my head lights.

If I do turn on any other running lights my tail lights get REALY dim to where you cant hardlly see them and I cant figure it out.
My center light is working good though but the cops don't care about that

Anyone have any ideas??

 

You have a bad ground wire somewhere.

Start with your main ground from the battery. Follow the wiring harness from the tail lights.

 

Sorry to say this, but in other words take apart your whole interior....