Wiring a U.S.A. Boat Trailer to a 9 Wire European Trailer Plug

Published 02/10/2010

Products Featured in This Question

5-Flat Trailer End 48" Harness

(42)

$11.40

Upgraded Circuit Protected Tail Light Converter with 4-Pole Flat Trailer Connector

(35)

$36.42

Hopkins Wiring Harness with 5-Pole Flat Trailer Connector - Vehicle End - 5' Long

(15)

$12.66

Hook Probe Circuit Tester

(61)

$13.33

Question:

Ok the 9 wires from the flat plug are: White, White/Yellow and White/Green are Earth No.3 (was female plug) The next 3 wires are: Brown, Brown/Yellow and Brown/Green going to No.5 Tail light (was male plug) The next one is Yellow No.1 left indicator (was male plug) The next one is Green No.4 right indicator (was male plug) The next one is Blue No.2 normally AUX or No.6 normally red for brakes (was male plug) The Brown/yellow left and the Brown/green right must be side indicators could not make it out yet. Even WESBAR the manufacturer was not able to help? Strange. Thank you for helping me.

asked by: Jurgen B

Expert Reply:

The 5-Way connector on your boat will be wired as follows. Green is right turn/brake, yellow is left turn/brake, brown is running lights (both sides), white is the ground or earth connection, and the blue wire is the reverse lockout or reverse lights. I searched for a connector on the internet that matches your 9-wire connector and came up with nothing.

I would recommend using a circuit tester, item # PTW2993, and wire by function only. Have a helper activate all of the various functions that you need for the trailer and test the wires until you get all of the wires needed identified. Since the boat carries the brake and turn signal on the same wire you will need a converter, item # 119178, to convert your vehicles European system down to a 4-wire system. You would then cut the 4-Way connector off of the converter and wire a 5-Way connector, item # HM37908 in its place connecting the blue wire directly to the reverse light circuit or reverse light circuit, whichever is needed.

expert reply by: Robert G

Juergen

2/10/2010

Bob G.

2/10/2010

I see that you have all of the wires figured out. With this information you should be able to get the USA trailer wired properly. The way I see it there are two ways to go about it. You have a 5 wire system on your vehicle and the trailer has a 4 wire system. You can either add two lights to the trailer to perform the brake light functions or you can use a converter, item # 119178, to convert your vehicles European 5 wire system down to a 4 wire system. In your case I would most likely add the brake lights so that I could keep the wiring on the vehicle the same and use a standard connector (for your country).