Originally Posted by
cuda
Long story short hooked up the boat to the truck tonight, grounded the tounge to the trailer body as suggested hit the lights same problem. Both taillights blinking when i call for either left or right signal. Recheck the grounds on the trailer, check the truck ground/ harness all is good. Dissconnect the left turn ground from the left trailer light now i have signals and brake lights working on both lights, but no cleareance lights. Reconnect the ground and everything goes back to crap. RECHECK all connections again, all are good try it one more time. STILL CRAP. Sit back have a beer think about this, its not rocket science, WTH. Start the truck up its getting dark lights on the truck come on automatically/ auto mode look back trailer clearance are on. Check signals, brakes, hazards all are working fine. Unplug the lights trailer to truck reconnect about 5 tries no issues. Unhook the trailer Reconnect it to the truck no issues. I can't explain it. I'm lost, AS of right now all is working fine. Going to hookup tomorrow just to see what happens. Ant idea about this mystery guys. I' m stumped.