I finished removing the fan switch and ruined it in the process, replacement is necessary I'm afraid. I was able to dress the wires and get them ready for the new switch when it arrives.
I tested everything again with the motor running and no problems. I waited til it got darker and also checked the back light on the voltmeter.
I had some time left so tackled the inertial fuel cut off switch. I tested the new one before I installed it, then removed the old one. The mounting holes were closer together on the new switch, so I had to drill a new one for the 2nd mounting screw. Space is limited there but it worked out. I finished wiring it in and tested it by making sure the fuel pump pressurized (I heard several clicks) when I turned the key. I then started the car and made sure it was getting good fuel flow by letting it run for a few minutes.
A little progress for the day.
The heater switch is ruined
New inertial cut-off switch installed
And wired in and tested
The backlight on the voltmeter works. Note the heater switch wiring ready for future hookup