Thanks for the info, Doc. Are you by any chance referring to the little disc with two wires attached to it on the side of the blower housing? According to the EPC (plate II under Heating and Ventilation for the 107) it's 002 821 18 51.

Over in the SL forum, however, someone stated that a stuck aux water pump can blow out a transistor in the control panel. Before I start tearing into the console, however, I'd like to get a better idea of what I'm looking for?