I have a 2002 F350 V10 and one night I turned the headlights on and when the ignition switch was turned to the off position the lights would go off.
When the ignition switch is turned off the lights come back on.
I changed the ignition switch but the problem still exists.
Has anyone else encountered this issue? And have a resolution?

 

Is the truck equipped with the Autolamp feature? DRLs?

Check fuse F7 under the dash?

Is the electrical wiring for the headlights stock or modified?

 

The truck is equipped with the Autolamp feature.
I checked the F7 fuse and it is good.
The wiring for the headlights is stock.
The issue happens when set to autolamp or manually turning on the headlights.

 

If the truck's electrical system is in the as-built configuration, the ignition switch should have zero effect on the operation of the headlights when the switch is in the HEADLIGHT position. It's a direct connection from fuse F7 through the headlight switch to the light bulb sockets via the MFS switch.

Verify with your meter or test lamp that fuse F7 is and stays HOT with the ignition switch in both OFF and RUN positions. Either there's something screwy in your wiring or your reporting of the symptom. What is the history of the truck and this symptom?