Adding a 4- to 7-Way Adapter with Reverse Circuit for Boat Trailer with Electric Reverse Lockout

Updated 04/11/2016 | Published 04/07/2016

Question:

I have a 2004 Honda Pilot wired with a 4 flat that I then connected a 4 flat to 6 round converter to be able to tow an older boat. This has worked fine in years past. We have purchased a newer boat that has a 7 way wiring coming from the trailer. I then bought a 4 flat to 7 round converter, unplugged the old 6 round and plugged in the 7 round. Upon plugging in the trailer, we have not been able to back the boat up. Every time I try to back it up, the trailer brakes engage and lock up. The old trailer we had did not have trailer brakes. I called the manufacturer of the trailer and they indicated that there is a 5th pin that goes to an electric reverse lockout solenoid. So my question becomes how do I wire my vehicle to disengage that solenoid? Any advice would be greatly appreciated!

asked by: Brian S

Expert Reply:

Your trailer has an electric reverse lockout solenoid. When energized it will prevent the brake fluid from flowing back to the brakes so that you can back up. All you need is to install a 4- to 7-Way adapter such as # 37185 (if you need to replace the one you have).

On the adapter there is a purple wire that you will need to tap into a reverse light circuit on your 2004 Honda Pilot. On the one you have the wire color may be different but as long as it is the one at the center pole then that is the wire you need.

I would not use a 5-Way adapter because you would just have to adapt it again to work with the 7-Way on the trailer and you would still have to tap into a reverse light wire behind one of the reverse lights.

Finding the reverse light wire is another thing. You will likely need to remove the panel on the rear hatch to access the wiring.

expert reply by: Michael H