Does it Matter Which Wire is Used on a Trailer Brake Magnet # BP01-110 as the Positive

Updated 06/13/2020 | Published 06/25/2011

Question:

is there a positive or negative end on the brake magnets

asked by: Frank P

Expert Reply:

No, you can use either wire as a positive or a negative wire. As long as current is traveling through the magnet in either direction this Trailer Brake Magnet, # BP01-110, will function.

I attached a video on trailer brake magnet replacement for you to check out also.

expert reply by: Jameson C

Sam P.

6/7/2020

I rewired a friends cattle trailer and used a 12-2 cable with black and white wires. I connected all the black wires together and all the white wires together but still no brakes. Did I wire it wrong ?

Chris R.

6/10/2020

Where do you have the white wires grounded? Can you tell me how you're actually testing the brakes after installing the new wiring?

Sam P.

6/10/2020

The white wires terminate to a ground lug in a junction box that has a solid ground to the trailer frame. The brakes are not working

Chris R.

6/13/2020

@SamP Got it. I'm not exactly sure what's preventing the brakes from working. It might even be unrelated to the new wiring and instead be an issue with the tow vehicle or brake controller. Have you tested the tow vehicle's 7-Way to make sure you're getting 12V power on the brake output pin when applying the manual override on the controller?