Underhood Wiring problems of the 2003 Chevrolet Venture

First we lost one of the speeds on the fan inside the van. Then about 2 weeks later we were on a trip and all was fine. We stopped for about 1. 5 hours and then continued to drive. When we had started out the second time there was an odor of something burning, so I pulled over and checked things out. I looked under the dash and could not see anything. I also felt the dash components to see if there was any thing that was hot, to which I did not see that much of a difference. I started the van back up and noticed that I could not turn the internal fan off and the smell of melting/burning wires was strong. I got home and took the dash apart and found that the fan switch had melted and wires to the fan switch had melted the insulation off. I took the switch out of the car so I can order a new switch and wiring harness. If I did not take the dash apart as soon as I got home, it could have caused a fire.