Quoted from Sk0r:1) Since the backbox flashers work with J107 is unplugged, does it mean that BR4 is not the culprit?
BR4 is fine.
Quoted from Sk0r:proceed to locate a shorted socket?
Pull the bulbs, remove wires from sockets. Hook things back up one at a time until you blow a fuse. Or get lucky and see something obvious.
LTG : )