Testing Wiring on a 1965 Scotty Trailer to Determine Wire Functions for Tail Lights

Question:

Do you have a diagram of the wiring? My camper has red wire and yellow wire for the left side and a red wire for the side marker and my wire harness has white for ground yellow for left green for right brown for tail lights. I need your help please

asked by: Christy M

Expert Reply:

Since manufacturers can use any wire colors they want for any function the only way to determine the functions of wires with any certainty is to test them.

There are a couple of ways to test them. First you can connect the trailer to the tow vehicle and activate each light function. Then test the wires using a circuit tester, # PTW2992, to see which wire has power when a given function is activated.

The other way is similar. You can use a separate 12 volt battery and power each wire at the trailer connector then test the wires. Once you have determined the functions of the wires I recommend labeling them!

I have linked our help article on trailer wiring for you. The colors used are common but by no means standard. Testing is the only way to know for sure the functions of the wires.

expert reply by: Michael H