How To Wire Brakes On A Tandem Axle Trailer

Updated 02/08/2021 | Published 02/04/2021

Question:

Hello, I have a trailer with two axles. The wiring is such that there are two wires going back to the vehicle, one for each axle. Would both of these wires be wired into the electric brake trough the connector on the vehicle SAE blue? Is this wiring better than one wire that is split at the brake location or does it not really matter? Thank you,

asked by: Robert M

Expert Reply:

Normally a tandem axle trailer only has one brake wire going to the vehicle, and it is typically blue. If you have two separate brake wires for your axles, that is fine and will not cause an issue. Having one wire ran along the trailer instead of the two wires you have is not any better or worse, it does not matter as long as the brake wiring is at some point connected together. The brake wires will then be wired to the electric brake circuit at the 7 way connector, which would later connect to the brake controller's blue wire at the front of the tow vehicle. I have attached a wiring diagram that will help out with this process.

expert reply by: Andrew N