BLOWER SWITCH

I am having an issue with my blower switch , it has melted the High part of the back of the switch, is Toyota having issues with to much amperage flowing through the small wires? and do you have to purchase a complete harness to repair this issue? thanks

 

I had that happen on my gen1 where the connector meets the blower fan. I went to the junk yard and found a new connector then spliced it onto the end of the wiring where the burnt connector was. I never had another issue with it. I suspect that if you just replace the switch you'll be ok. Maybe you got a defective switch from the factory?