okieiniowa78

I have heard and read awesome things about this forum... I am an avid owner of many different F-Series trucks over the years from an '81 to '06 in various configurations. I am seriously in need of some direction from y'all on this '91 I am buying. None of the interior or exterior lights work, neither does the radio. The blower fan works though, so the cab isn't totally void of power. Where do I start? Should I pay someone to diag and fix??? Direction... Please?

Forge-World-FORD

Simple stuff, check the bulbs easiest to get to just to make sure none are blown. Check ALL fuses and relays in both the cab panel and the under hood distribution box.

5Rangers

Besides what Forge said you my also want to consider checking the fusible links coming off the hot side of the starter relay.

okieiniowa78

Thanks for the input. The kid I'm getting it from said the problem started shortly after he was messing with the aftermarket radio. There was a spark from the wire that runs to the cigarette lighter. Just wasn't sure what all ran off the circuit that controls the headlights, and if the interior lights were on the same ciruit/relay.

5Rangers

Which lights specifically don't work?
Headlights, running lights, turn signal lights, brake lights, emergency flashers, instrument cluster lights, overhead dome light.

If we know that specific information we might be able to nail it down to one component.

Ford runs different lights off different circuits. I could be all day posting pictures and explaining.

okieiniowa78

The headlights, taillights, dash lights, radio, dome light are all dead. The turn signal and brake lights work fine.
Thank You for trying to narrow this down.

5Rangers

Headlights are powered by fuselink L, Exterior lights/ fuse 4, courtesy lamps/fuse 8, also fuselink L, cluster illumination/ fuses 10 & 11, and radio/ fuse 11 powered by fuselink M. If M was open there would be a lot of other things not working. The only thing in common to all of these is the main light switch.

I'm confused a little bit because not only your rear park but also your front park lights should be out and you specified tail lights only.

Also, turn/stop and hazard lamps don't go through the light switch which would explain why they are working.

Here are testing procedures:

donpagel

I'm having similar problems. As well as the dash lights, my turn signals have recently stopped working. I've checked all the fuses, replaced the signal flasher AND even replaced the signal switch (that was a pain in the &$!. Any ideas? Do you have a similar testing chart for the turn signals?

okieiniowa78

Just the brake lights and turn signals work. No parking lamps work, no headlights. Dash and dome are dead. No power to the radio either.
From what I'm gathering from your reply is the headlight switch may be to blame here?

5Rangers

Yes.. main light switch.. you can ring it out with a meter to make sure..