1991 F150 Weird electrical problem

For several years now, this F150 has an electrical issues in the winter months. What happens is that when I start the truck, the accessories (radio, air, windshield wipers, turn signals) will not work for awhile, but will eventually come on. What’s odd is that there seems to be no rhyme or reason as to what it takes for them to start working.

For example, this morning I set out, and after a few miles the accessories came on. I stopped, shut the truck off, and a couple minutes later took off again. The accessories were off and stayed for for even longer this time, but still came on within a few miles.

Sometimes it only takes a minute for everything to work, sometimes longer. Once it took nearly 45 minutes. The only thing I can say for sure is that this doesn’t happen in the warm months.

I’ve checked fuses and grounds, and everything I’ve seen looks good. What should I try next, a priest?

How about a DVM? You don’t need to drive anywhere. Just start the truck and start following the connections from battery to fuse box and beyond until the loss of voltage indicates the problem area.

This sounds like what happens when you first turn the key to start the truck and all other accessories are temporarily turned off, only in your case it is longer than temporary. Your truck is the right age to need a new ignition switch. That is my guess.

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The crimps holding the ignition switch together loosen or break resulting in intermittent contact inside. The ignition switch is inexpensive.

You may just have a weak return spring in the ignition switch. Next time it happens turn your key slightly to the left. Lf that fixes it you can either replace the switch or just remember to turn it back to the run position manually.

I had a 93 f250, if the steering wheel was tilted all the way the turn signal would not work, so for kicks try changing the tilt on the steering wheel!

I think oldtimer hit it my 82 dodge does the same thing I do what oldetimer said work’s every time.

I posted this the other day for someone else as I had troubles as well, the headlight switch melts on these model years . Numerous things are connected into the switch and as it warms and cools things acted up.
Check out Sparkys page, photos and all https://sparkys-answers.com/2009/01/1990-ford-f150-pickup-no-headlights.html

Hey guys, thanks for all the answers! Sorry for the delay. We’ve had flooding, so my wife has needed the F150 to get to work, and some very warm days, so no electrical problem.

But this morning it was nice and frosty out, 36 degrees, and the accessories didn’t come on. Jingle the key backwards and bingo! there they go. I’ll get a new ignition switch in there soon.

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What you all are describing is actually the ignition lock. The switch is located farther down the steering column and activated by a rod that the lock moves via the key.