Use the 7 pin connector anyway see below and just leave out the last 2 wires. Trailer wiring diagrams.

Trailer Wiring Diagram And Installation Help Towing 101
Boat trailer wiring diagram 5 way. Use on a small motorcycle trailer snowmobile trailer or utility trailer. The first step in wiring your trailer cables is to ground the white cable first. Where to attach trailer side 4 way 5 way 6 way 7 way 7 way 6 way 5 way 4 way right turn green 18 16 right turn of vehicles wiring harness. Lowest prices for the best wiring from optronics. Auxiliary wire signals trailer brakes to disengage when in reverse. An extra pin allows using another extra function.
5 pin trailer wiring diagram download. Utility trailer 03 4 pin trailer wiring and diagram duration. Boat trailer wiring diagram trailer wiring junction box diagram. 5 pin boat trailer wiring diagram collections of wiring diagram for a 7 round trailer plug inspirational 5 pin flat. For a 5 flat trailer end connector for your ranger boat trailer a great choice would be the wesbar 5 pole flat connector w002290ive attached a link to a video review of this harness for you to take a look at. Episode 2 of 3 in the boat trailer remodel and how to make your trailer fit your boat.
It gets complicated when you have trailers with more cables and in this case you need an adapter to make the connections. Wiring your four pin trailer can be a challenge when you first do it but its a simple do it yourself task. By law trailer lighting must be connected into the tow vehicles wiring system to provide trailer running lights turn signals and brake lights. 34 inch by 1 inch 6 way rectangle connectors right turn signal green left turn signal yellow taillight brown ground white. Can also be used as custom wiring on trailers with 3 lightwire systems. The red and blue wire can be used for brake control or auxiliary.
5 wire trailer wiring diagram. Trailer electrical connectors come in a variety of shapes and sizes. If your truck has a built in 7 pin socket but you only need 5 of the pins. This often happens when a boat trailer is backed into water with the trailer wiring still connected to the vehicle. The basic purpose remains the same whether your truck and trailer is using a 4 way 5 way 6 way or 7 way connector. A wishbone harness means that there are separate wires for the running light circuits one for each side of the trailer.
In the trailer wiring diagram and connector application chart below use the first 5 pins and ignore the rest. 5 way trailer wiring diagram allows basic hookup of the trailer and allows using 3 main lighting functions and 1 extra function that depends on the vehicle. 4 way flat trailer wiring diagram pics.