I have no fuse in my ign B socket. also have dual batteries but if the main is dead the other will not crank my motor. this as an 8.1L gasser came with the dual battery is the ign b for the second battery? not really sure how GM has the dual battery system wired. truck is a 2002 year

IGN B is nothing more than another keyswitched circuit feed, and it's not used on all applications.

In a gasser, battery number 2 is only available while running. Follow the positive lead from number 2 and it will lead back to a solenoid that is BCM controlled. It looks like a ford fender-mounted starter solenoid.

thanks it was actually the ign A that had no fuse in it. i got them mixed up after i shut the hood yesterday.