Join Date: Aug 2010
Location: Freakin' cornfields
iTrader: 1 reviews
Hard to make heads or tails of those schematics, but what it sounds like you're looking for is more on the fan side than the CCRM side. Basically your chassis provides power at the low speed pin for, well, low speed, and then when it reaches the high speed threshold it provides power at the high speed pin, just the high speed pin.
For it to make the fans have a high and low speed, they have to be two speed fans of some sort, either with a ballast resistor or dual windings.
What the factory one does is use a ballast resistor. It's pretty inefficient, but that's how it is. Basically there's only one real circuit through the fan motor itself. But with the low speed pin, it goes through a resistor first. You're basically switching the resistor on and off, depending on which pin gets power. Low? Pre-resistor (with). High? Post-resistor (without). And the CCRM is already the relay, so you just take the juice straight from the fan pigtail, no other relays required.
How are your fans configured?
FWIW, I'm running Intrepid fans. They're pretty good for flow, cheap, and very low profile. I believe they're dual winding. All I had to do was match wire to wire. I basically just slapped a matching pigtail on it and it worked.