Replacing 5-Way Connector with 8 Wires on Boat Trailer

Updated 11/29/2019 | Published 11/28/2019

Products Featured in This Question

Pollak Black Plastic, 7-Pole, RV-Style Trailer Connector - Trailer End

(669)

$7.94

25 Ft 5-Way Trailer Wiring Harness - Wishbone Style - 30" Ground - 5' Auxiliary Wire

(66)

$16.61

Deka Heat Shrink Butt Connector - 16-14 Gauge - Nylon Insulation - Blue - Qty 10

(1077)

$15.53

Cordless Circuit Tester

(14)

$19.65

Question:

The wiring harness on our boat trailer is bad. There are NO replacement plug that looks like ours. It has 5 pins and eight wires coming out of bottom. One blue, one green, one yellow, two brown and three white. One of the white ones has a brown line on it. Anyway total of eight wires. Looking for a wishbone harness still only has 6 at most. How can I find one with eight? I have searched and read all forums to help us with this. But have found no answers. I have included a photo. Please help. I wanna go fishing!!

asked by: Jana J

Expert Reply:

We definitely have what you need to replace the 5-Way connector on your boat trailer, but there's not going to be a pre-made 5-Way harness that includes 8 wires. As you mentioned the most you will likely find is a wishbone harness like # A25W5B that uses 6 wires (a separate running lights circuit wire for each side of the trailer). A previous owner or the factory simply used a non-standard wiring setup when installing the connector and wiring on your trailer.

With all of that being said, it's still going to be easy enough to swap out the connector. Your best option will be to simply cut off the existing 5-Way and replace it with a new one like the above-mentioned harness. Since a 5-Way doesn't usually have 8 wires, you will just need to test each of them for function with a circuit tester like # PTW2979 when connected to the tow vehicle or by simply applying 12V power directly to each wire if you aren't connected.

Once you know the function for each wire you will be able to splice into the new connector. On the 5-Way # A25W5B the white wire is ground, the brown wire with green stripe is right side running lights, the brown wire with yellow stripe is left side running lights, the yellow wire is left side stop/turn, the green wire is right side stop/turn, and the blue wire is auxiliary/reverse.

If I had to guess you most likely have a few ground wires on your current setup (but I still recommend testing to be sure) so you will probably just have to splice in multiple wires from the trailer to the ground wire terminal on the new 5-Way. I recommend using heat shrink butt connectors like # DW05744-10 to provide a good seal to avoid any shorts from exposure to the elements (especially since it's on a boat trailer).

If you have any other questions along the way please feel free to reach out! We want to get you fishing again as quickly as possible.