On any circuit that draws enough current to heat at the fuse to contact points plastic will deform as most plastics go questionable at about 180 degrees. I always treat contacts with some form of anti corrosion paste when cleaning and renewing grounds etc.

I kind of know then in all likelyhood I will never have to do it again. Eventually car manufactures started doing the same on many plug connections. I really see it as good maintenance of these older cars anyways. I do not think the manufactures really expected these cars to still be running this many years later when originally built.

When the blower motors get a little older. From bearing drag etc they draw a little more current. Unfortunatly our digital meters have a current maximum of ten ampres. So you cannot read that circuits actual draw with out constructing a shunt for the meter.

A shunt is so easy to build to increase the amperage reading ability. You should look up meter shunts on the web. Basically just a piece of household wiring a foot long. Follow the simple instructions posted on using it.