Back in Feb of 2012 someone posted this schematic of E-fan wiring...
https://www.ford-trucks.com/forums/11...-add-leds.html ... I am planning to use the same plan on my 98 Windstar fans for my F250. I already have a Hayden single fan controller with an adjustable thermostat ...fine so far!!! my questions are #1. what is the start/run amps on each of those fans (for circuit protection) and #2. It is recommended to use a diode to fight "power feedback" ... where in the heck do I put the diode I am not an electrical student at all ???

The last time you helped me was with my wiring and installation of my 3G alt back in March ... thanks to you it works PERFECTLY ...NO ISSUES "0" !!!
I have also passed on that info you gave me to help others that were stumped too !!! If you can help with this project ... it would be appreciated a bunch !!!
Dave

 

Here's an article from another forum. I am reading that it must be around 30 to 40 amps draw on the large fans(there is a small fan and a large fan per windstar or taurus?).
electric fans...take 2

Diodes are used to clamp the spike you can get from a coil or motor when the power is removed. The diode is installed across the motor leads, but backwards. The band on the diode is hooked to the + lead and the opposite lead to the negative.

The other place you will need a diode is if you are running A/C. You will need at least one fan to run at all times if the A/C is running. So besides your signal from your controller to activate the relays, you will also need to get a signal from the low pressure switch on the A/C system and tie it to one of the relays. Problem is, if the A/C is off, and the controller kicks in and sends voltage to the relay, the voltage will go backwards up the wire to the low pressure switch, and run the compressor with the A/C off. So in this line to the A/C low pressure switch a diode needs to be installed to block any current from traveling backwards up this wire.

 

Hey Dave Thanks again !!! I was planning to run a separate relay powered by the B+ from the "A/C clutch" and have that second relay move power to the "A/C fan only" I also was going to manual override switch on the dash to also activate the second relay ... I think I got that right ... Oh yes, I'm planning on using circuit breakers in place of fuses for my electric system protection. And yes I was planning to on both systems. Thank you for your help on this project too... I'll keep you posted on the job !!!!
Dave