I recently bought a 2002 F150 to tow my boat. My boat requires a 5 pin connector (trailer has electric brakes) but the truck only comes with a 4 and 7 pin. The dealership installed my five pin by splicing into the 4 pin and running the extra 5th wire to one of the wires in the 7 pin. I told the dealer to splice into the reverse lights for the extra 5th wire but they said the 7 pin connector has a reverse light wire so they tapped into that instead.

Next time I took out the boat the brakes were engaging in reverse. I checked the voltage of all seven connectors in the 7 pin plug and there's no voltage to any of them in reverse.

Is my dealer wrong or do I have a bad 7 pin connector?

Thanks for you help.

 

I've never seen a 5 pin connector, but.. from what you've said, I can gather this: the four pins on the "four pin" connector on the truck are for the marker lights, and one for each of the signal lights on each side. The other is for the ground. The colors of these are- yellow is the left turn/brake light, green is the right turn/brake light, brown is tail lights and clearance lights. White is the ground. If you have electric brakes on your trailer AND backup lights, you are going to have to have at least a 6-pin connector for all of this. I'm not sure, but.. usually the backup wire is orange, and the brake wire is a blue of some tint. To run the trailer brakes, you are going to have to have an electric brake controller installed in your truck.

 

My trailer has hydrolic brakes put are deactivated when in reverse by the fifth wire in the harness. Does that make sense? Otherwise, when I reverse the trailer, the trailer "feels" like my truck is slowing down and applies the trailer brakes.

I guess my main question is, does the 7 pin connector have a wire that has voltage when the truck is in reverse?

 

Yes. The center pin on the factory installed 7-pin connector is the backup light circuit. You do need the backup relay installed in the PDU box to energize this circuit.

 

Thanks Jimb, that's exactly what I needed to know.

 

Remember you can look on the lid to the light hookup for all the info on what pin is what.