My brother has a 2003 Chevy Silverado 2500 HD and purchased recently a dump trailer (he's a landscaper). When he hooks in the trailer plug, everything works as it should except when he hits the brakes, the trailer lights turn off rather than lighting the second filament. How can this be fixed?
Also, the trailer has electric brakes. What is going to be needed to hook this up? Is there already something on the truck to hook this up? Thanks in advance.
You will need a brake controller to do the brakes. his truck should have came with a wire harness in the glove box for it. it will have 4 wires. 12 vollts, ground,brake light in or signal and electric brake out.wire acording to the brae controler diagram. Now for the lights. A new 2500 comes with a factory 7 waay and i have never seen one wrong from the factory so i would start with the trailer. test the wires on the 7 way by powering them up one at a time til you find the problem. i have seen plenty of trailes wired wrong from the factory. here is the wiring diagram.
https://www.drawtite.com/6and7waywidi.html
If **all** the lighting works; turn signals, parking lights, markers, etc, and everything goes dark when he hits the brake then I'd suspect a bad ground.. I'm assuming the truck has a brake controller already installed.
You could measure voltage from the trailer frame to the truck frame when stepping on the brake pedal, or use a pair of jumper cables from the truck frame to the trailer frame as a temporary ground path to verify.. Electric brakes draw a fair amount of current when applied.
Jim