Adapting a Semi Truck 7-Way to RV Style 7-Way to Use Wireless Light Kit to Flat Tow a Van

Updated 06/18/2015 | Published 06/17/2015

Products Featured in This Question

Hook Probe Circuit Tester

(66)

$14.45

Roadmaster Brite-Lite 3-to-2 Tail Light Converter for Towed Vehicles

(130)

$55.75

Question:

I transferre simi tractors . I bought wireless lights for my tow van that I tow behind the simi tractor it has a rv 7 way plug transmitter it will not hook up to the 7 way plug on a simi tractor. I was wondering if yall had adapter that would hook in the simi tractor and the 7way rv plug transmitter?

asked by: Mike L

Expert Reply:

There isn't an adapter to go from a semi-truck 7-Way to an RV style 7-Way, but you could hardwire in a separate RV style 7-Way on the semi-truck. You can use a circuit tester such as # PTW2993 to test the wires at the back of the semi 7-Way. It should have separate circuits for each turn signal and brake lights.

If so, then you will need to combine the separate circuits using a converter # RM-732 because an RV style 7-Way has combined turn signal/brake light circuits.

On the converter input side, the white wire is ground, the red wire is brake lights, yellow is left turn signal, and green is right turn signal. On the output side, yellow will be combined left turn and brake and green will be combined right turn and brake.

You can wire those output wires to # 37185. You would just cut off the 4-Way part of this adapter and wire the yellow and green wires from the converter to the yellow and green wires on the adapter. On the 37185 adapter the brown wire is for running lights. Ground the white wire to the truck frame.

The other wires you will not need if you just need the light functions to work on your wireless light kit UNLESS the wireless light kit gets power from the 12-volt circuit. If so, you would also need to wire the black wire from adapter 37185 to the 12-volt circuit on the semi 7-Way.

expert reply by: Michael H