Question:
Im replacing the tail lights on my trailer and my trailer has three wires per side and each tail light only has two
asked by: Brian A
Expert Reply:
On each side of your trailer there is wiring for the turn signal/stop light circuit, the running light and the ground circuit. Your taillights have two wires only because they ground through the mounting hardware which normally attaches to the trailer's metal frame. So you need to determine the function of both wires on you assemblies (one will be stoplight/turn other will be running light) and then wire to the trailer's wiring you have found as well by function.
