Dick and Doug,
Good find you two on the schematic (which are at best hard for the not so gifted like myself to figure out) and the button thermostat. Dick can you describe where that is exactly in the engine compartment ceiling.
So here is what I think is happening in the design. Going to the CFR (cooling fan relay) are connections for battery power, relay out to fan, battery power, and thermostat. This uses a common single pole single throw Bosch style relay. Battery power is supplied to one leg of the relay switch, the other leg of the switch goes to the fan. The relay coil that activates the switch has 12V power on one side and the other side is connected to the thermostat in the engine compartment that Dick found. I think the thermostat is in series with the relay coil and feeds the ground side to the relay coil. If that is so there should be 12V on one side of the thermostat and the other side should go to ground.
If you jumper that thermostat Dick see if the fans start. If that is so, my suspicion is that the relay version they chose has no diode across the coil and that inductive kickback kills the thermostat contacts over a short period of time. I say that because the relays are quite reliable and so many of us have no functional fans so there must be a design flaw in the thermostat side.
The other possibility is the thermostat itself is junk. Both of these issues can be resolved fairly easily. A diode could be installed across the thermostat and a better thermostat by design can be sorted out.
Dick or Doug if you get a chance jumper that thermostat and let me know what happens. In case I am wrong on the design do just a very quick jumper across. There may be a little arc, that would be normal. I am pretty sure that this is the design and the fans should start.
Later Ed