On my 96 F350 i have only 6 volts to headlight switch power at B1 connector that supplies hot power all the time but should be 12 volts. On the B2 connection for park lights I do have 12 volts.
My problem is that I have no headlights hi or low but the flash to pass lever works fine. The headlight switch test good but the 6 volts coming in to switch is the problem. I do have 12 vots at the 40 amp fuse that protects that circuit. Any one know what could cause this 6 volts at the plug that feeds head light switch? I guess I have to trace the harness from power dist box and see if chewed up wires. Truck sat since last snow storm

 

Are you measuring it with the switch connected or disconnected?

Is this a Canada-spec truck with daytime running lights, by any chance?

 

No day time running lights, not from Canada.
It is 96 F350 Chassis truck.
I measure the volts with headlight switch removed from connector.

 

was broken wire under power distribution box

 

I run relays out under the hood feeding right off the battery. and just use the wires from original headlight to run relays.
these work well
http://www.summitracing.com/parts/via-80238/overview/
I just unplug wires in the sockets to feed like I want. but they build a harness that is plug an play for a little more. even though you get 12v out there a harness will make them brighter and wont pull as much through the switch. If you've ever had your headlights go out while driving at night you know what I'm talking about