Can 12V Circuit on 7-Way Trailer Connector Run a Pump

Published 07/14/2021

Question:

The fill rite pump has a black and red wire. The ground wire is by itself on the outside of the pump. How do I connect these wires to the 7 way connector to make it work in the plug. Thank you

asked by: Chett

Expert Reply:

The red wire on the pump should be power and the black ground. You can simply attach the ground connection directly to the trailer frame using a ring terminal on the end of the wire or use the main trailer ground which is typically found on the trailer tongue.

Assuming that the pin in the 1:00 position on on your vehicle's 7-way is active, you can possibly use that circuit to run your pump assuming that the pump's power requirements aren't greater than the 12v trailer circuit is usually fused for, which is typically 30-40 amps. You can confirm that checking the trailer charge fuse location in the tow vehicle's fuse box, to make sure it'll provide enough power to run your pump. If it will, you can connect the red wire to the 12v circuit, see the linked wiring diagram.

You might also consider a battery isolation solenoid like # PK5231201. The solenoid will power down the 12v circuit when the vehicle's ignition is off, so you don't run down the battery.

expert reply by: Mike L