My 1990 f150 that I just bought had some small issues. The fuel tank switch wires were cut and added to a toggle switch. The a/c fan speed would not work on any speed except very low.

I went to the junkyard today to get the correct factory parts and noticed that some of the trucks had melted plug ends. My a/c speed selector did also.

I rewired the factory stuff back in place with solder and shrink wrap. All seems to be working as it should now. It looks better also. Is the melted plug an issue that can be remedied?

 

Everything was too small. Wiring got hot and melted the plugs.
I don't see it as an issue as long as the heater isn't on high for 5 hours straight.
My mustang almost caught on fire due to the headlight switch. I b ought the new plug for it and haven't had an issue since.
The heater is a heavy draw also. Make sure the fan isn't half bad and causing a big amp draw.