Got a 93 d250 went to leave this morning no head lights.as long as I held the dimmer switch lights stay on.then pulled switch it and out got them to work any idea what would cause this I saw something about rewiring them but does this sound like the problem

 

Could be the headlight switch, the multifunction switch, or one of the connectors to either.

The headlight relay mod would prevent a re-run of this damage in the future, and also add a bit of brightness to the lights.

 

The wiring harness plug going to the switch also tends to melt a bit too.

 

Thanks for the info bad thing is now there working and I can't find the problem

 

This kind of problem points to the headlight switch. The multifunction switch bypasses the headlight switch so they can be used as passing lights.