I understand that the F27 provides power to the brake control module when we install it (2015s, 2016 non-diesel?) If you read my description of my brake control installation, I pulled that fuse for the very reason Reverendbiker mentions he popped the fuse accidentally. It also allowed me to install my wiring without having to disconnect the battery ground and worry what I might be resetting with all the crazy electronics on the trucks.
http://coloradofans.com/forums/114-...rum-2015-gmc-canyon-forum/197346-diy-brake-controller-hookup-2.html#post2934313
Well, I sure appreciate the efforts you have made here. The reviews you have provided here have been invaluable to me - there is no way I would have been brave enough to install a brake control module on my truck prior to reading your installation instructions you did a year ago. The interesting thing is I have personally wired 100 amp, 480 VAC 3-phase motors, have wired sensitive electronics, installed power supplies, memory chips, etc. in computer motherboards, and have supervised and instructed technicians on dozens if not hundreds of installations of industrial machinery & equipment, most of it being 480 VAC 3-phase equipment. But the idea of ripping a plastic panel off my $35K truck and attaching 4 wires to a controller on a 12 volt DC circuit scared me till I read your instructions.