PWM radiator fan controller

[terrydmorgan]

There doesn't seem to be a lot of interest in the pwm implementation so far, but I'll post what I've learned in case interest blooms in the future.

My implementation involves an E67 ECM, so this info is peculiar to the E67, but may have application to other ECMs as well.

E67 Pinouts that need to be added are all on the J3 (grey) connector.
AC Pressure Sensor
J3-21 (ground) wire color black
J3-37 (5V) wire color grey
J3-57 (AC pressure signal) wire color red/black
PWM output
J3-49 wire color green

PWM Fan Control Module - AC Delco 15-80803
Pinouts
1) Fan (-)
2) battery (-)
3) Battery (+) fused
4) Fan (+)
6) PWM output from ECM (J3-49)

AC Pressure Sensor from C6 Corvette
Pinouts
1) ground (connect to J3-21 on ECM - wire color black)
2) 5V (connect to J3-37 on ECM - wire color grey)
3) Pressure signal (connect to J3-57 on ECM - wire color red/black)

The following programming changes need to be made to the E67 ECM
1) Set PWM fan control on, instead of discrete fan control;
2) Repopulate the following tables with your desired fan speed vs. temp/pressure values:
a) Coolant temp/fan speed
For example, 204 Deg. F (at 10% duty cycle) and increasing with temp up to a max of 90% duty cycle at 235 Deg. F and higher.
b) AC pressure/fan speed
For example, fan speed 10% at 160 psi up to 90% at 260 psi for Vintage Air implementation



If you haven't purchased a radiator fan yet, you may want to consider the fan assembly from a C6 Corvette as it is made to work with the PWM controller and even includes the correct electrical connector. I've seen it advertised for around $120. Try searching for Dorman 621-102 Radiator Fan Assembly.