Yes, that is what is happening. The cleaned original switch and the new switch are causing the fuse(s) to fail no matter which position they are in.
I have also spliced (& tested) all new wires between the pillar and the door thinking the cracked insulation (all were cracked but one). I was convinced I isolated the problem to the switch but the failure of a new switch is the cause of my confusion.
Has there been a change in design of these switches? My next step will be to pick up another new switch to try.
Thanks for all your responses.