TruckCO

Hey,
I have a 91 F150 XLT Lariat that recently developed a turn signal issue. Here is the behavior:

Start truck, turn signals work fine

Put truck in gear, turn signals still work fine

Push on gas, turn signals stop working and remain not working until turning truck off and back on again.

I replaced the signal flasher, but that didn't fix the problem.

Any thoughts?

FosterChild

Could have a power surge from the alternator. Make sure it is charging 14v

Forge-World-FORD

Does it not change if you push on the gas while parked or in neutral?

TruckCO

If I push on the gas while still in park the signals still work.

Forge-World-FORD

And neutral? Just curious, what transmission do you have? Do the hazards still work when the turn signals stop working? Brake lights light up like there supposed to when you hit the brakes? Press the brake and operate the turn signal, any difference?

Forge-World-FORD

Also, pull codes just in case it brings up something that could be related.

TruckCO

The problem has gotten worse. Today, the radio stopped working while I was driving. After I stopped the truck and then tried to start again, it now won't start. It turns over, but isn't catching.

I was testing yesterday to see if it was something in the steering column, and I was able to make turn signals stop working without putting truck in gear or moving just by turning steering wheel all the way to one side. But, it might also be that the truck was running for a little while and had nothing to do with the steering.

It's an automatic transmission. The headlights seem to still work. I haven't tested the hazzards.

TruckCO

Problem solved. The ignition switch was bad. Difficult to get to, but cheap to replace.