Trailer Lighting

[Gregory OConnor]

Like Kurt said. but if the wires match,

sounds like the bus brake is either seperate wire like the european
setup or an E brake. when you hit the bus brakes it is picking up a
electric brake addon actuator signal and sending it to the trailer. at
the trailer the e brakes are shorted out or the wire it connected to at
the trialer plug is the trailer ground. if the trailer ground is the
wire crossed, the ground you now have is that which is made via the ball
and chains. I would unhook the ball and chain and see if the proven
functions still work.

you dont need a brake wire on federal apps unless you have e brakes on
the trailer.

stop and brake are different lables. stop is the light and brake is the
e brake shoes. but some times if the diagram has not both, stop or brake
is the light!!!!!

You can test the trailer for a short by using a multimeter prior to
plugging it into the bus. use ohms or continuity function. ground one
lead to the trailer frame and poke at the plug to find the one pin that
sounds the buzzer or shows no resistance. that is ground. if you find
another pin without resistance, one of the two pins is not intended to
be continious to ground and is mostlikely the fault.