A long while ago, the OEM engine fan and fan control circuit both failed, and I didn't have a clue where the fan control module was located, didn't have a Haynes either. So I just got a temp sensor/fan control relay at Autozone for 25.00 or so, and it has worked fine for fan control. The replacement fan is only a single speed unit, not dual speed like the original. See the attached JPEG of the schematic for fan control.....
I looked close at that schematic today, and noticed that there is a wire coming off of each temp sensor/switch (high and low speed) and going to the LH Jetronic system, I suppose to the ECU. I need to know what these two inputs are for, and if they are there to adjust idle speed, mixture, or what? I am wondering now whether this could cause engine performance to be adversely affected somehow, since the ECU can no longer sense when fan is turned on? THe idle speed isn't a problem as teh increased electrical load when the fan turns on isn't dropping the RPMs. Buying a dual-speed fan and a dual-speed fan control module wold cost a LOT!