Connecting a Trailer w/ 7-Way to Vehicle w/ 4-Way Connector

Published 12/29/2011

Products Featured in This Question

Pollak Circuit Breaker - Cycling/Automatic Reset - 40 Amp - Straight Mount Bracket

(49)

$7.70

Question:

I would like to use this as a just in caseinch tool with my trailer. The trailer has brakes and a 7-way, but if I find myself needing to move it with a vehicle that only has a 4-way, Id like to use this for short periods of time to power the lights. Lights only is better than nothing if you dont have a brake controller, right? If that is all it is for, can I splice the loose white wire into the white wire that is part of the 4-flat? Wouldnt that attach the lights to ground? Is this not how it is by default so that you dont overload wire that is only supposed to handle light current?

asked by: Daniel

Expert Reply:

You could wire the Tow Ready Adapter 4 Pole to 7 Pole # 30717 and just have the light functions on your tow vehicle without connecting the other wires. But I would be very cautious about not doing so for several reasons.

The first reason is safety. The general rule for towing trailers with brakes, is that if the Gross Trailer Weight is half of the Gross Vehicle Weight, it is recommended to use a brake controller and have brakes on the trailer.

Not being able to activate the trailer brakes can be dangerous. The weight of the trailer will act as a force to keep pushing your tow vehicle forward as you are trying to stop. As you may know, the more mass a traveling object has, the more force it takes to bring that object to a stop. So, with your vehicle connected to a trailer, you are adding more overall weight but not increasing the braking power.

The white wire of part # 30717 would need to be connected to a clean metal surface, like the vehicle frame.

I can understand that the cost of adding a 7-way and a brake controller to your vehicle may out weigh the benefit of only being able to use it minimally. If you find yourself towing with different vehicles, you may want to consider the Prodigy RF Brake Controller # TK94FR. The RF Controller mounts to the trailer and allows you tow with various vehicles as long as there is a 7-way on the vehicle and a dedicated power from the black wire on the 30717 adapter to vehicle battery via a 40 amp circuit breaker # PK54540. For wiring, you will want to use 10 Gauge Wire, part # 10-1-1, which you will need to measure to determine how much wire you will need. It is best to order more than needed to make sure you have enough.

I have linked instructions for the Tekonsha Prodigy RF Brake Controller # TK94FR.

expert reply by: Reno H