I have a 96 f150 with a 5.8L V8.
My blinkers have stopped working and I have no idea why. I checked the fuses and they're fine. The 4 way flashers still work. Another thing I noticed is that it also seems that a bulb or light behind behind the instrument cluster is not working because right where my fuel level and battery level are, it's darker than it was.
Any ideas???

 

just one thought..... it may not apply to your truck. I had a 68, and a 75 f-150.. both had badly worn turn signal switches. I bought an aftermarket switch first... wrong thing to do... so coughed up the money for a ford part... and wham-o ... problem solved..

 

does your truck have an aftermarket plug in for trailer lights?.. I have a 75 f-250 now, and it had connection problem when I got it ...it had no signal lights... cured it but it took some crawling under the rear to check it all out.
I also had a bad brake light switch once on and older ford that caused turn signals to not work

 

No after market trailer lights, brake lights good too. Only thing that I notice is the instrument cluster light seems duller, like a bulb or light isn't working there. Otherwise all other lights are fine

 

There are two separate relays...one for your hazards and one for your flashers. Just a thought if you haven't checked. Maybe swap one for the other and see if the flashers work.