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Discussion Starter #1 (Edited)
installing a Crown Vic 2-speed e-fan setup which is similar to the Taurus fan but fits my radiator better. im going to make my own relay kit. question is does the low speed relay need to turn off when the high speed relay is on? or can both low and high speed relays be on at the same time?

i have seen diagrams showing how to wire the 2 relays so it turns off low speed circuit when high speed circuit is on. but then a 3rd relay is needed so fans only comes on with key on. otherwise they will stay on after engine is off till it cools



otherwise if it is ok to have high and low speed powered at the same time, i can use just 2 relays just like a dual fan setup

on Derale's FAQ page, it says the dual fan controller can run a 2-speed fan like a dual fan setup. tho it does say it will not support high amp fans like the Tuarus and such so i was going to make my own relay setup. but i dont want to damage my fan motor so i want to make sure

Q: Will the Hi Amp or PWM controller run a 2-speed fan?
A: Yes. The Hi Amp controller will run each speed as if it were two separate fans meaning the Fan #1 wire would feed the Low speed wire (gray) and the Fan #2 wire would feed the high-speed wire (brown).
This controller Will Not Work using the following 2-speed O.E. Electric Fans: Dodge Viper, Ford Taurus, Ford Contour, or Lincoln Mark VIII. These fans exceed the amperage & functionality capabilities of this fan controller.
Ford EVTMs dont really say. they have low and high speed on separate relays and each controlled by the PCM. does show the low speed on a 30a fuse and high on a 50a fuse so it does draw a good amount of power
 

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run the power through the NC contacts on the high speed relay, before going through the low speed's NO contacts

when Hi speed is needed it will open the low speed circuit

simple
 
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Discussion Starter #3
picked up few relay blocks from junkyard from a 2000s ford/lincoln inclueding one that had 4-relays in the block. the high speed relay being bigger does not have a NC contact so it required 3 relays. the 4th relay i used for a pusher fan anyways. took alot of soldering but got it wired up and working. have it setup with the BMW 2-speed temp switch as well as a 3-posiiton rocker switch for manual-on / manual-off / auto. unfortunate the junkyard did not have any Volvo relays. more unfortunate i ordered the DCControl 2-speed controller but the lead time being several weeks and i needed it running in a couple weeks for an event
 

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Everytime I wire up fans I always use and highly recommend two relays in parallel for each fan speed.

Otherwise thats a lot of current for one relay and you could have failure. Its not worth it to risk it.
 

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Discussion Starter #5 (Edited)
well im using the OEM fan relays that Ford used for these fans so it should be fine. downside being the high amperage relays for high speed doesn't have a NC termial. my EVTMs show low speed should be on 30a fuse and high speed on 50a. my pusher fan is jsut a cheap universal that draws 11a but i may replace it one day

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This is how the factory Contour fans are wired with a 2 speed fan switch (Contour OEM is triggered by ECM). I got mine from a 2000 Audi/VW 1.8 turbo car where it is mounted in the radiator tank. I fabbed a mount for the lower rad hose using an axle nut from a Contour (M22x1.5 thread)

Contour Fans Schematic with AC.jpg

I also wired in a toggle for each speed so that if I wanted I could manually trigger the fans.
 

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its all pcm control
 
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