70-72 Heater Fan Switch Issues?

[Donbarnes]

Were these prone to any special issues, like catching on fire? The 72 I just got had one wire melted off the side of the plug on the back of the fan switch and somebody put a new end on the wire, then there was a ground wire going to the relay in the corner behind the glove box that had all its insulation melted off and had a little singed area in the sound deadening like it tried to catch on fire. The PicknPull near me has a 70, and when I got the heater controls out of it the brown wire on the back of the switch had also melted the whole side of the plug out on it...