Anyone know where the fuse is located for the factory-supplied wiring harness for electronic trailer brake controllers? Mine blew when hooking up my Tekonsha Prodigy to my 2004 GMC Sierra 2500 HD with the Duramax. It had power momentarily until I inadvertently touched a contact to metal, blowing the fuse. I've pulled dozens of fuses, and nothing is labeled logically, all to no avail. Help, anyone??