Question about fan control on 740 - scan0002.jpg (0/1)

  • Thread starter Thread starter geronimo
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geronimo

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!
 
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