What are the Wire Functions for the 5-Flat Trailer End Wiring Harness, # 20017
Updated 05/27/2011 | Published 05/26/2011
Question:
trailor wire s blue green brown yellow white new wire harnes has yellow and brown together white green and brown together and blue wie my problem is i cant get left turn signal to work cant figure out wire diag no diagram was in box please help me thanks
asked by: Al
Expert Reply:
The 5-Flat Trailer End Wiring Harness, # 20017, is what is a called a wishbone harness. The brown wires contain the running light signal. It is split at the plug and ran to each side of the trailer so you do not have to have a jumper wire between the two tail lights. So the wire that is yellow and brown goes to the driver side for running lights, and the green/brown wire goes to the passenger side for running lights.
The all yellow wire contains left turn and brake lights. The all green wire contains right turn and brake lights. The white wire is the ground and needs to be connected to a clean bare metal surface on the trailer frame.
The blue wire can be for a couple different functions. If the trailer has a surge brake coupler with electric reverse lockout OR reverse lights, the blue wire would be ran to one of those. The corresponding pin on the vehicle would then be connected to the reverse light circuit.
If the trailer has electric brakes then the blue wire could run to them. The corresponding pin on the towing vehicle would need to be connected to a brake controller to engage the trailer brakes. However, this wire is not a heavy enough gauge to effectively carry the voltage required to actuate the brakes. If the trailer has electric brakes, I recommend upgrading to a 7-Way wiring harness on the vehicle and trailer. I would need to know the year make and model of the vehicle to make the best recommendation.
If you have everything wired as explained above and the left turn still is not working there is probably a bad ground at the tail light itself and you will need to clean the attachment point or move the ground to a better location.
If towing with a motorcycle, the bike could have a different wiring configuration that is not converted/ does not match the trailer. You would need to test the wiring harness on the bike using a circuit tester like # PTW2993, to make sure the 20017 harness is compatible or if a converter is needed. On many bikes, the brake signal is separate from the turn signals.
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Michael H.
5/27/2011
The 5-Flat Trailer End Wiring Harness, # 20017, is what is a called a wishbone harness. The brown wires contain the running light signal. It is split at the plug and ran to each side of the trailer so you do not have to have a jumper wire between the two tail lights. So the wire that is yellow and brown goes to the driver side for running lights, and the green/brown wire goes to the passenger side for running lights. The all yellow wire contains left turn and brake lights. The all green wire contains right turn and brake lights. The white wire is the ground and needs to be connected to a clean bare metal surface on the trailer frame. The blue wire can be for a couple different functions. If the trailer has a surge brake coupler with electric reverse lockout OR reverse lights, the blue wire would be ran to one of those. The corresponding pin on the vehicle would then be connected to the reverse light circuit. If the trailer has electric brakes then the blue wire could run to them. The corresponding pin on the towing vehicle would need to be connected to a brake controller to engage the trailer brakes. If you have everything wired as explained above and the left turn still is not working there is probably a bad ground at the tail light itself and you will need to clean the attachment point or move the ground to a better location. If towing with a motorcycle, the bike could have a different wiring configuration that is not converted/ does not match the trailer. You would need to test the wiring harness on the bike using a circuit tester like # ALL640595, to make sure the 20017 harness is compatible or if a converter is needed. On many bikes, the brake signal is separate from the turn signals.