I posed this question on my explorer board but I usually get faster responses here

Last night the headlight switch in my 91 Explorer starting acting up. Depending on how I played with it I could either get parking lights or headlights and no parking lights. I went out a bought a new switch and just put it in. What I noticed was that one of the terminals on the old switch was burnt and the connector in the harness was also semi-burnt and the plastic was melted. The insulator on the wire was also discolored. After replacing the switch all still works.

My question is could this have been caused by the way I have my off road lights wired up? My off road lights are not high power, just simple 55W x 2. I have the power for them tapped into the parking lights so that they can be turned on anytime the lights are on. They are wired with a proper wiring harness including a relay. So could this have put too much load on the switch, or was the switch just faulty after being 17 years old? Ive had this setup for almost 4 years now...

Just for reference the H/L switches in the early explorers are known to have issues. Also I know the way I have the lights wired isn't the best but I want to be able to use them anytime and I can't run power direct to the battery or the stupid light on the switch will be on all the time.

 

Perhaps you need to use a relay...you might be overloading the headlight circuit

edit: I just read that you already are using a relay.

 

just an update...
Today I took everything back apart to fix the wire. Turns out I can't find any connectors like the ones used by Ford. The good news is that the wire was still perfectly intact, only the insulator was damaged. I wrapped it with electirical tape and put it back together. Enjoy...