Trailer reverse light wiring

The ABS uses the “hot” wire, and there is a reverse circuit also.

Bumper pull trailers use 7 wire connectors, and I’ve installed backup lights on my bumper pull dump trailer, and use the hot wire to keep the battery charged.

Anyway:

It doesn’t matter what me or any other Internet expert says, there’s plenty of conflicting information ( and diagrams).

Have your mechanic find the pin that goes hot when you shift into reverse, and that’s your backup circuit.

You could also have a push button on the trailer to latch a relay, drawing power from running light circuit. To unlatch the backup lights, turn off the running lights.

LED lighting draws so little current; you shouldn’t have a problem.

 

The 7-round on the back of your pickup is NOT wired the same as a 7-round on a class 8 truck.

7-round RV plug, the left & right turn signal wires double up as brake lights. Then you have tail, ground, aux, reverse, and electric brakes.

The 7-round plug on a large truck has left & right turn signals, brake lights, tail lights, marker lights, ground, and ABS (or aux power on an older truck). There is no wire for reverse.

 

This^^^^ just wire you up some reverse lights on a switch tied into another light.. just would have to remember to flip switch on and off for when you want back up lights..

 

Or set up a 2nd plug for aux items like reverse lights.

 

That's how the white lights on the back of the gooseneck horse trailer operate...run off the aux power circuit with a switch at the rear of the trailer to turn them on. They're actually more like loading lights...pair of switches for the interior/exterior...but can be used to see where you're going backing up.

 

That's the only way I've ever had work lights on a semi trailer. We had side dumps that used 2 pins on a 6-round, so I just picked a different pin and wired up the work lights on the tank I usually pulled.

 

Many, if not most, of the trailers I've encountered are wired with ABS constant power on the center pin (blue wire) of the 7-way plug. I've always thought it would just be easier to run an auxiliary cord with whatever number of conductors needed for the extra lighting, and tie it to the reverse switch on the tractor side. Used plenty of trailers with a manual switch somewhere and it's irritating to get out and switch them on and off.

 

We'd typically rig up a 4 pin cord on log trailers for the digital scales. If we were ambitious we could have run additional lights on the other 2 pins.

 

The work lights on our tank trailers are simply tied in to the tail lights somehow. Using a toggle switch. Which don't last btw.

Obviously the tail lights have to be on for the work lights to work.