The heater/AC fan wasn’t working right. Getting at the switch to test it was impossible without removing the console cover. That’s easier if I remove the seat. Work seems to take two steps forward and then one back!
This is the switch to control the fan based on the setting on the heater/AC sliding switch. Fortunately it can be opened up and cleaned. It was coated in old stiff grease. I cleaned it up with electrical connector aerosol fluid and coated the contacts with dielectric grease.
This is the fan switch disassembled. A bit hard to see. There are four tangs holding the switch together. I bend them back just enough to open it up. It was also coated in old stiff grease. Cleaned and coated with dielectric grease and re-assembled.
These type of mechanical switches have been in use since the 1950s. They are not hard to get apart and can be cleaned and put back in use. The contacts are usually copper and so there is no corrosion.
The fan now works as it should. Now to test out the vacuum lines for the heat, vent, defrost and AC.