If not, and if I have to put a 5 wire connector on the truck, where does the blue wire connect?
you will have to run a trailer brake controller for 5 wireno adapter for this. The feed from the controller can't be shared with any of the other funtions.ex. tail lights, brakes lights, ect. I wouldn't go for a 5 wire. Just go straight to a 7 way plug that has every thing. A blue wire is usally 90% of the time the standard colour for a brake controller wire. I know that is how my plug is wired. And buy the way, a good 7 way plug has the colours marked on the back of it to show you where to put the wires by colour. Last two cents here, you can buy a 4 wire adapter for a 7 way plug. Always easier to go down then try to put one more then what you need. hope this helps and isn't to confusing .
I think you will find that one of the wires is for your trailer brakes. The other 4 are the tail, signal l, signalr, and grnd.Is your truck wired for trailer brakes?
your boat trailer has surge brakes (an actuator in the trailer tongue senses increased pressure as the trailer pushes against the car when braking and activates the trailer brakes). The fifth wire in the connector, which will be blue, disables the trailer brake when the car is in reverse so that the trailer brakes do not lock up while backing the boat down the ramp. The easiest way to get around replacing harnesses and connectors is to tap into the wire that feeds the back-up lamp bulb, run an independent wire that you you can plug directly into the 5th opening on the trailer harness, and the bypass will work as planned. This allows you the flexibility to switch back and forth with other trailers that use a four-way connector as well. One caution, when not in use, make sure the end off the added wire is covered so it wont short out on the vehicle body and blow a fuse when backing up. If you are going to change the connector to a five-way, the blue wire is still connected to the back-up lamp circuit.
