So far your car guy sounds right. If I remember correctly, the fan switch is screwed into the upper right (passenger) side corner of the radiator. another way to test this switch would be to first, find the switch. Then unplug it and short the 2 wires together (that is all the switch does anyway). I can't remember if the ignition needs to be on or not, so first try it without the ignition on.

Listees, please correct me if I am wrong.

Sean B.
'90 V'gon, "Happy Bus"