Can 4-Way with 4 Wires be Used with 4-Way with 5 Wires

Published 10/05/2017

Question:

Can a 4 prong 5 wire trailer harness be hooked up to a vehicle with only 4 wire setup. If so how ?

asked by: Mark B

Helpful Expert Reply:

Yes, the 4-ways with 4 wires and the ones with 5 wire perform the exact same functions so they both can easily be used together.

What you have a picture of is a wishbone 4-way that has the two running light circuits on it. One for either side of the trailer. That's why it has 5 wires. The 4-wire 4-ways use a single wire for this circuit but you then have to split it off to either side of the trailer. The two wires in your picture that have brown on them are that circuit.

# A20WB is an example of a wishbone 4-way like what you have.

expert reply by: Jameson C