Electrical Gremlins

[Bruno2]

91 F 150 351 W E4OD 2WD.

The truck is having some intermittent power failures to different points inside the cab.

It is happening to components fed through multiple switches. IOW, it's not just the ignition switch or just the headlight switch circuits.

The truck had some voltage issues with a bad starter and bad positive cable causing a pretty vicious amp draw on the starter relay.  I tried to jumo it over at one point when the starter was bad and it melted the insulation of the jumper wire to my fingers.

[Steve83]

If you're not going to list EACH affected component, and the exact conditions under which you've observed the faults, or post pics of the battery & starter relay, we're not going to be able to help much.

[Bruno2]

Ok, so today's issue was the blower motor wouldn't come on. When the truck went into reverse it began to work. Almost as if the movement of the vehicle caused something to make contact again.

The other night all of the interior lights including the radio went off. However, the truck kept running as if nothing to do with the motor was affected. The power windows and locks wouldnt work either.  Just the things inside the cab are affected.

This doesnt happen on a regular basis,  just interment and heals itself.

[Gary Lewis]

This sounds like an ignition switch issue.  The switch can make some contacts and not others, and I've certainly had situations where the truck ran but some things wouldn't work.

So have Kris try turning the key back ever so slightly from Run towards Off and see if it helps.  And the instructions for removing, cleaning, and re-installing the switch, along with adjusting it, are here: Electrical/Ignition and on the Ignition Switch tab.

[Bruno2]

I will have him try that and report the results.

Thanks!