1996 Dodge Van NO POWER TO HEADLIGHT SWITCH

The power feed wire to the hardlight switch is dead.
i used a jumper and gave that wire power at the fuse box and the lights worked fine. I need to know how to find out where the power should be coming from to power this wire.
with the ignition switch off I have power to one wire in the fuse box. When I turn the ignition switch on I have power to three wires on the fuse box. But not to the wire that should feed power to the headlight switch.
in the fuse box does it have one main power supply wire and the wire loops to the other power supply wires when called for?
could there be a connector problem in the fuse box?
if so how would I find that?