7-Way Recommendation for Activating Trailer Brakes on a Trailer with a 5-Way

Updated 02/22/2013 | Published 01/31/2013

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7-Way Round RV Style Trailer Connector - Trailer Side

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$13.57

Question:

I have a utility trailer with tandem electric brakes and a 5 Pin Flat connector on the tounge of the trailer. The trailer is currently powered by a 4 Pin Flat connection with the 5th Pin of the trailer connection exposed no brakes. My tow vehicle has a 7 way blade female connector. I presume the unused blue wire on the trailer is for the electric brakes. Will the A75TB adapter power the electric brakes using the correct 5 wire connection? Thank You!

asked by: Kevin F

Expert Reply:

Typically, the 5th circuit of a 5-way is for a reverse light circuit. I have a solution for you, but you will not be able to use the Adapter 7 Pole to 5 Pole Flat # A75TB to activate your trailer brakes as it has an empty port where the brake output circuit would be on your tow vehicle connector.

I would recommend you confirm that the fifth circuit on your trailer is actually for trailer brakes. You can do this by tracing the wires back from the connector and see if they go to the brake assemblies.

If the fifth circuit on the 5-way does go to the trailer brakes I would recommend you cut off the 5-way and then install a trailer side 7-way like the 7-Way Round RV Style Trailer Connector # A7WCB in place of it. You will want to wire it up according to the picture that I attached.

expert reply by: Jameson C

click to enlarge

Kevin F.

1/31/2013

Jameson, thanks so much for your answer. It was very helpfull and super fast. I received my first order from etrailer the other day and have been very impressed!! This Q

Patrick B.

2/8/2013

We are glad to help, let us know if we can help with anything else.

Daniel H.

2/17/2013

what if i do not have a purple wire.I hook up everything and everything works but the brakes.6 way to 7 way 2004 40 ft. Ameritrail flatbed going to 2010 Dodge truck.thanks

Patrick B.

2/22/2013

The purple wire, center pin, is typically used for reverse lights. If your truck has an OEM 7-Way, from the factory, it should be wired this way. Use a circuit tester, like PTW2992, on the 7-way at the rear of your truck and have someone inside activate the manual over ride to be sure the signal is making it back to the 7-Way. If it is not, then you have a problem somewhere on the truck. If it does make it back, the problem is probably with the wiring or brakes on the trailer. The adapter you have could also be wired to a different standard. In which case, if you only use the Dodge, you may want to replace the trailer 6 way with a 7-way, like part A7WCB. Simplify the setup and get the trailer set up with a more common connector.