Plain Jane OEM nothing to see here rebuild

[Pete_89T2]

Originally Posted by vrracing

According to your drawing your switch is a 207/194. My understanding of how the switches worked is that the circuit closes (fan comes on) at the higher temperature (207) and stays on until it reaches the lower temperature (194). Then the engine warms up to 207 and the process starts over.

Actually the 2 numbers in the switch spec is just a way for the manufacturer to cover his ass and define a repeatable tolerance. In this case, the mfg. guarantees that the switch will close/turn on whenever the temp is greater than anything in the range of 194 to 207*F. IOW, they guarantee it will be open/off at temps < 194, and closed/on at temps > 207. Another way of doing this is to specify a single temp switch point (e.g., closes @ T > 197), and include a tolerance factor, (e.g., +/- 10%).

Originally Posted by vrracing

Does the 1.7 show voltage? IIRC the 2.1 does.

Logging voltages is a good suggestion... Unfortunately the Rtek 1.7 lacks the serial port to allow tuning/logging with a palm device that the 2.x has.

Originally Posted by JustJeff

The good news is the car is home, I had no issues with it. I'm going to test a few things tomorrow morning. See if my alternator might be failing and simply not up to the task of that hog of a Taurus fan.

That's what I'm thinking, if the alternator can't sustain a steady voltage of at least 13V while running all electrical loads and charging the battery, things will get wonky. Which is why I agree monitoring voltages on the next drive is a good idea. That Taurus fan has a colossal current draw, and can quickly discharge a battery. When you were running the fan on the manual switch for a prolonged time, I think the battery discharged deep enough so that the alternator couldn't support all the electrical loads AND charge the battery, so as soon as system volts dropped below 12 or so, fuel delivery and/or ECU control started failing.