Can a 4-Way Flat on a Truck Be Used with a Trailer 5-Way Flat without Connecting Extra Wires

Question:

I am going to be using a moving truck to haul our house and boat. The moving truck has a 4-prong and my trailer has a 5-prong flat. What is the simplest way for me to convert the moving truck to support a 5-wire, recognizing that its a rental? I watched the video and it seems straight forward except I dont want to open their light housing if I can avoid it. If I dont hook up the 5th wire to the truck, will this freeze the brakes when going forward - or is that wire only for reverse?

asked by: Chris H

Expert Reply:

I recommend using the Adapter # 47515 or # 20036 and not connecting the extra blue wire to anything on the truck. On a 5-Way flat connector, the extra blue wire is normally for an electric reverse lockout which you find on a lot of boat trailers.

The brakes on the trailer are probably hydraulic with a reverse lockout on the coupler. The blue wire sends power from a reverse light circuit to a solenoid on the coupler that does not allow fluid to pass through to the brakes when the vehicle is in reverse. This is so you can back up without the brakes engaging.

If you will not be backing up during the trip, you really do not need to have that blue wire connected to anything. But, chances are that you will need to back up and not having the electric lockout can be a hindrance.

All you need is access to a reverse light wire on the truck and create a temporary connection from the blue wire on the adapter to the wire. I would call the rental place to make sure you can do it.

expert reply by: Michael H