I monitored the output and tested some knowns. When I run the A/C compressor this runs the fans at 50% from previous tests.
I tried to monitor the PWM signal using this line:
value = pulseIn(pulsepin, HIGH, 1000000);
I got values such as 229, or 99.
What happens tho is when I turn the A/C compressor on, it reads 0!
Not believing that - I metered it and saw 4.9V.
I need a way of doing it such that I can differentiate between line idling high, and line remaining low and allowed to go high.
I know that when the fans are not needed, the wire reads 0V (so I think the ECU continually drives it to 0V when it wants no fan - which makes sense, wiring harness gets damaged then it should remain '5V'...
I like '1' better - any thoughts on a circuit for that design (i.e. smooth the pwm to a voltage and feed to analog in).. This would give me great proportional control.