Trailing wiring issue

[jasonb]

i used to have my harness plugged into the little round plug under the bumper for years. worked fine. last time i hooked the trailer, only the running lights worked. checked current at the wires just before the factory plug and only the one that supplies juice for the tail lights was showing current. i'm assuming there is a relay somewhere that controls the left/brake right/brake lines but i couldn't find it. followed the wires as far as i could without luck. had to splice into the brake line just to get by for now. guess its ok since nobody uses blinkers anyway!
someone mentioned in a thread while searching that replacing the multifunction switch helped some of their trailer wire issues. i know mine is bad. is this possibly the relay for the plug back there as well? thanks.

 

[Crankcase]

With the signal on.....do you hear the relays clicking at all?

Also...try the 4 way flashers and get back to us...
The 4 ways have nothing to do with the mutlifunction switch.

 

[jasonb]

when my blinkers work, i can hear it clicking like normal. is that what you mean?

will try the flashers tomorrow. all i have hooked up is the tail lights and the brakes right now. both wired directly into the lines going to the tail light housing on the truck so ill need to the harness back to try it.