cjoe,
I don't think a bad connection at the headlight plug would affect the switch contacts. A high resistance connection usually results in heat at that point, and decreased current flow through the system.
Were your light switches both new, and did they both fail in the same manner?
If the lighting circuit is fused before the light switch, and the system draws too much current, the fuse would probably pop.
I think poor contact on the switch points themselves could cause a heat buildup, and subsequent failure. The contacts should be rated for more than enough current if the switch is a quality item...if the switch is from India or Malaysia, it might not be up to snuff.
Stuart
