Can an Electric Trailer Tongue Jack Be Wired to Trailer Lighting Circuits

Published 01/06/2015

Question:

I want to put an electric jack on my trailer. My trailer does not have a battery can I wire it into the trailer lights.

asked by: Jeremy Y

Helpful Expert Reply:

It is not possible to wire any other electrical components, apart from lights and low-power items such as the on-off circuit for a backup camera, to the lighting circuits on a trailer. Connecting any power-hungry device to lighting circuits would result in excessive current draw and could potentially damage the trailer wiring harness and/or the wiring in the vehicle itself.

A tongue jack like the Stromberg Carlson Electric Trailer Jack # JET-5000 that you referenced will pull 25-amps at its rated 5000-lb load. This is several times the maximum current capacity of even the beefiest wiring harnesses. Also, the 12V trailer power circuit on a tow vehicle's trailer socket does not necessarily have the required current capacity to operate a jack. The wiring would have to be quite heavy in gauge in order to support the jack's current demands. I recommend against this.

To use a powered jack on your trailer you will have to install a trailer-mounted battery.

Once you have your 12V battery in place on the trailer installation of the jack is simple. The ground connection is made through the mounting hardware. It often helps to sand off the paint from the bottom of the jack mounting flanges and from the trailer surface with which it will make contact. This ensures a solid ground connection which is essential for proper jack operation. The only other connection to be made is for the 12V positive power wire, which will connect to your trailer-mounted battery hot terminal through a fuse of the appropriate value for the particular powered jack you choose.

expert reply by: Adam R