Can Redarc Tow Pro Liberty be Tested/Calibrated without Trailer Connection

Updated 12/09/2025 | Published 11/17/2025

Question:

Hi, I bought a Redarc tow pro Liberty for my 2012 pilot. I installed the unit and checked that it was getting voltage from the car and a brake signal from the car as well. I don’t have a camper yet, picking up soon. How can I make sure the unit is calibrating since it does not light up with out a trailer? Are there pins I can jumper on the 7pin connector to make it think there is a trailer. Just want to make sure it’s okay before I go to tow my new to me trailer. Thanks Will

asked by: William S

Expert Reply:

Hey William, in electric mode the Redarc Tow Pro Liberty you have will look for the amperage draw of trailer brake magnets on the 7-way 5:00 pin before it will show a connection...but if you put it in hydraulic mode it would just need to see a connection so you would want to put it into hydraulic mode and then if you use any type of circuit tester it would register it as a trailer connection and would allow you to verify it is working.

As far as calibrating it without a trailer I don't think you can do that effectively so I would wait till you have a trailer.

expert reply by: Jameson C

Jameson C.

12/8/2025

Hey William, how did things go once you picked up your trailer and tested the Redarc Tow Pro Liberty? Did the controller calibrate and show a proper connection in electric mode? Your update could make it easier for others setting up the same brake controller.

William S.

12/9/2025

@JamesonC I happily saw the light on the dial come one once we plugged into the camper The lights also flashed showing the calibration as we started driving. Thanks for the follow up Will