Fan controlled by computer (ECU)

[vlydeka]

I have EEC4 computer on '89 Ford 302 engine (stroked to 331). Planning to get quarter horse chip to be able to tune my car. Now I'm looking for options how to control my electric fan.
One of the options, which I like the most, is to control the fan with the computer. Has anybody here done it? I looked online and it looks like I need to use PIN 41. If I understand correctly, I need to run dark green wire- Fan Thermo Switch (fan relay ground) to the PIN 41 and then set desired fan on/off temperature in the bin file?

[2boss]

...is a much better place for such ?'s.

[hotmansweep]

hook a wire to the ac wire, that wire will be your switched overide,the ac wire always turns the fan on

[vlydeka]

Originally Posted by hotmansweep

hook a wire to the ac wire, that wire will be your switched overide,the ac wire always turns the fan on

I see that it could work for overide switch, but I don't understand how ECU will control fan based on coolant temperature. Explain please

[Rob]

http://oldfuelinjection.com/files/A9L_E-Fan_How-to.pdf

[vlydeka]

Originally Posted by Rob

http://oldfuelinjection.com/files/A9L_E-Fan_How-to.pdf

Thank you, Rob. I found this document online earlier today. Here is where I have a question:

Text from the document
Testing Pin 41
In order to test whether or not pin 41 goes to ground (once the
required temperature has been reached), we need to use a 2k ohm ½ Watt
resistor and a voltmeter. Using a voltmeter by itself will indicate
that Pin 41 is grounded 100% of the time.
1.The + of the voltmeter goes to the + battery.
2.The – or COM of the voltmeter goes to the 2k ohm resistor on one side
along with pin 41.
3.The other side of the resistor goes to the + battery.
This will load the circuit in order to keep from getting a false signal
to ground.

1. Do I have to do this test when ECU is connected to the harness and power is supplied to the ECU?
2. What setting I should use on my voltmeter and what signals I should get if pin is grounded?