The sockets may be bad since they have power going to them. Did you check for power at the sockets?

 

Have you checked the bulbs?? I assume you would have but nothing mentioned about it...

 

all the bulbs are fine, no filaments broken. takes play with the switch but they all function

 

Sounds like you got a bad switch, or the wires aren't making contact due to the melted plug.

 

I didn't check for power at the sockets yet, no. I'll try that and keep you updated.

 

Ok hope it was just bad sockets makes it easier.

 

Check the sockets first. If you have no power there, check for continuity on the switch. Try jumping the switch. If your lights come on, bad switch. It's common for them to go out, that's why they switched to relays on late models.

 

Very common on these trucks. If the switch socket is showing signs of damage there is a good chance that the switch has failed. On my 94 and 95 I installed a relay for the headlights after my 83 failed without warning one night. Fortunately the switch is easily replaced. Do check the grounds and headlight wiring as resistive connections will draw more amperage.
Regards
rikard

 

ricard,
how about a write up on how and where you put the relay in?
thanks ken

 

Put them under the hood, power from the battery and the old light feed becomes the trigger.