Are Brake Controllers Supposed to Receive Constant 12-Volt Power

Question:

I have a 1999 f250. Is the black 12v wire from the main harness always supposed to be hot? Even with the key off? I plugged my brake controller in and it has a red dot always on

asked by: Tom

Expert Reply:

The power feed to the brake controller does indeed remain on when the vehicle ignition is off. Most brake controllers will go into power down or sleep mode after 10-20 minutes of inactivity. When in sleep mode, the controller will use a miniscule amount of power, you'd need to leave the vehicle unattended for months on end before you'd need to worry about this power draw depleting the battery. If you're concerned about the power draw or are planning on parking the vehicle for an extended period of time, you can always unplug the harness from the brake controller. Just don't forget to plug it back in before towing the next time.

expert reply by: Mike L