'86 F-250 Supercab. No dash lights. Replaced headlight switch as headlight occasionally flicked off and on, fixed that but not dash lights. Fuse is not blown. With lights on I have no voltage at either terminal of the headlight fuse.

Does anyone have a wiring diagram for this truck? Pinout on the headlight switch? Or know the path of electric to the dash lights? Anyone come across this before? Any other fuses or fusible links in this circuit? Thanks for any help!

 

The dash backlighting is on its own 5A fuse - light blue/red stripe wire.

Look up a post by 85lebaront2 and follow the link in his sig, I think he has the EVTM for your year (or real close) on his site somewhere.

 

try looking here i have the schematic if you need them best luck. https://www.ford-trucks.com/forums/picture.php?albumid=34879&pictureid=125146[/IMG]

 

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This is the fuse I meant, not the headlight fuse. I get no voltage at either terminal of the dash light fuse with lights on. So wherever that feeds from, I assume the headlight switch, is the problem. I'll try to trace that wire, blue/red stripe sounds familiar.

 

if its the 5 amp your refering to you may have a blown fuse link between the battery and the fuse panel.[/IMG]

 

Turns out it's not just the 5 amp fuse as position 17. 15 amp fuses at positions 4 and 8 also feed the headlight switch. #4 was popped, replaced and now dash lights work. Easy fix, but didn't figure it out until after pulling dash off and removing headlight switch to trace wires. Hopefully it doesn't pop again, if so I'll figure out what's causing it.

 

Iy's been a while since I've looked at the schematics but, as I remember it, the headlight switch gets its feed from a fusible link under the hood (always-on power) and the headlamps are governed by a circuit breaker in the switch. From there, the switch breaks things out into several different circuits which are themselves protected by the fuse box.

There is a tan/white wire in the headlight switch wiring that is famous for melting and cross-circuiting wires, might ensure that's doing OK.