I have a 93 f-150. The truck runs fine until I turn on the headlights, then it dies. I have checked the fuses and relays but still success. The running lights do not affect it, just the headlights. I did notice that my right turn signal light on my instrument panel lights up when I turn the headlights on. Any Ideas? thanks

 

Where to start... You are pulling more juice than your alternator is producing

Check your battery and alternator first

 

Did you find a solution? My 95 F150 is doing the exact same thing! My indications are the same as yours. Any help would be appreciated.