eHoefler wrote:
Check your umbilical cord to the vehicle, and the connections in the junction box on the the trailer. You have a poor/loose connection some where.
DITTO.
It's probably a loose umbilical cord at the truck receptacle.
On the trailer cor, take a screwdriver and move the electrical contact to cause more "spring" tension when the cord is plugged in to the truck.
Also check the truck and trailer connector for dirt, grit, grime, corrosion.
And NEVER use
one these caps to "protect" the trailer plug. They cause more problems than they solve. This video I made proves it.