dumb wiring question

[pdfd]

ok I have a 2002 sierra and I hooked up my trailer, I used the wire adaptor to go from the 7 pin to the 4 pin, everything works but when I press the brake pedal the trailer lights go out.. I have replaced all the wiring on the trailer, and it still does it,, anyone have an idea

[dosser]

Sounds like you have managed to put your lights in "series" with each other. Make sure your lighting circuits are "parallel".