I just finished replacing the radiator, water pump, hoses, tensioner bolt, belt, thermostat, pressure tank cap, AT front hoses, spark plugs, distributor, rotor, and engine mounts. I also recently cleaned the idle control valve and replaced the adjacent vacuum hoses.

I had thouroughly drained the coolant. After installing all the new parts, I removed the screw on top of the aluminum housing over the thermostat, and dumped distilled water into the expansion tank until it burbled out of that opened screw hole. I replaced the screw, put the cap back on the expansion tank, and started the car. I turned the heater control to 85 degrees. Even after the car had clearly warmed up, the blower never turned on. I think I tried every combination of buttons for the fan and the direction of the vents. The blower never went on. Why?