Can I Power the etrailer A-Frame Jack Through the 7 Way to Pull Power from Towed Battery?

Updated 09/02/2025 | Published 08/13/2025

Products Featured in This Question

etrailer Electric Trailer Jack - Drop Leg - A-Frame - 18" Lift - 3,500 lbs

(245)

$129.96

etrailer Trailer Wiring 7-Way Upgrade Kit w/ Junction Box and RV Style Connector

(361)

$56.04

Electric Jack w/ Footplate and 7-Way Plug - A-Frame - 25-1/8" Lift - 3.5K - Black

(1891)

$199.94

Question:

Im looking for an electric A frame trailer jack for a roughly 3,000lbs 2 horse trailer. Would e23ZV be a good fit? Also, the trailer does not have a battery and is powered solely by the tow vehicle with a 7 pin connector, could I wire the electric jack to a 4 pin connector to supply power from the tow vehicle?

asked by: Kyle

Expert Reply:

Hello Kyle,

Yes, our etrailer Electric Trailer Jack - A-Frame - 18" Lift - 3,500 lbs # e23ZV would be an excellent fit for your 2-horse trailer at 3,000 pounds.

A 4-flat trailer connector only carries lighting functions (tail, turn, brake, and ground), so it does not provide a 12V power source and therefore cannot be used to power an electric jack. To run the jack from your tow vehicle, you’ll need to use the 7-way connector, which includes a dedicated 12V auxiliary power circuit. Connect the jack’s positive lead to the 12V pin on the 7-way (typically the black wire at the 1 o’clock position when viewing the socket face), and connect the jack’s ground wire securely to the trailer frame, which is tied back to the tow vehicle through the 7-way’s white ground wire. With this setup, the jack will draw power directly from the tow vehicle, and its built-in 20A automatic reset relay fuse will protect the motor from overloads or short circuits.

If your trailer has a junction box, a kit like the etrailer Trailer Wiring 7-Way Upgrade Kit w/ Junction Box and RV Style Connector # e99011 makes it easy to route the jack’s power lead cleanly through the 7-way system.

If you wanted to skip all of that, you could go with the Electric Jack w/ Footplate and 7-Way Plug - A-Frame - 25-1/8" Lift - 3.5K - Black # EJ-3527-BBX which already has the 7 way on it.

What kind of horses do you have? I showed a little Western when I was a kid, my show horse was a Appendix Quarter Horse names Turbo who was more like a big dog than a horse. It was one of the saddest days when we had to put him down, first time I ever saw my Dad shed a tear.

expert reply by: Kate F

& Way Trailer Wiring Diagram
(click to enlarge)

Kate F.

9/2/2025

Hey Kyle, Did the Electric Jack with the 7-Way Plug work out for your trailer? I'm curious to know how it went because it could really help others looking to simplify their setup.