Flat 4 Pin Trailer Wiring. Put a flat connector tester into plug on truck and it only shows running light working and not turn signals. Cut the four-pin plug off of the trailer harness.
Having the various pinout diagrams available is vital to troubleshooting and/or repairing. Trailer Wiring Diagrams showing you the typical wiring for most single axle trailer and tandem axle trailers. Here's my question: How do I check my wiring at the hitch to make sure everything works as it should?
Many times, trailer wiring is as easy as inserting the trailer plug into your vehicle's pre-rigged system.
There should be a common color for both the tail lights.
In fact, most vehicles, especially those meant for The good news is that the standard connector for trailers uses four pins, plus the ground. Hooked trailer to wife's Ranger and lights OK. It is easier than you think.