Since I'm in the process of gathering my parts and information for an e-fan setup, I thought I'd start a thread where we could have one spot for a lot of the commonly looked for information to do this. Here's a quick overview of what I'm in going to build:

• I'm going to use a Ford Taurus 2 speed e-fan (comes from the early to mid 90's 3.8 Taurus & some other Ford products),
• I'm going to start with a relay based controller rather than a Pulse Width Modulated unit. My reason for this is that I've already built relay controllers and have had a reasonable amount of experience testing my design (it's not unique, there are only so many ways of making 2 speeds work with switches) and am happy with the performance and also have many of the parts that I want. Anything new would require a fair amount of testing to prove the whole functional tree and the unit durability - I'd hate to end up on the side of the highway with an overheated engine because I rushed through the process.
• Currently, I plan to use 3 SPDT 40/30 amp relays (they don't all need to be this size but I'm using what I have), 1 small Ford solenoid (about 85 amps or so is good), 2 DPDT toggle switches for Manual/Auto Selection as well as Hi/Lo/Off selection, 2 thermal switches (temperature values TBD), and a handful of LEDs, Diodes to cut out the flyback voltage, and maybe even a warning buzzer.
• The 3 relays will be used as follows:
  • One for the Air Conditioning - to switch the fan to high regardless of what it's selection may be,
  • One is for the Lo speed selection, and
  • One is for the Hi speed solenoid activation - I've had much better luck using cheaper, lower value relays to actuate a heavy duty solenoid than I have using expensive heavy duty relays. The one heavy amp line is connected only to the solenoid.

I'm currently in the process of making my schematic which I'll post here for comment when I'm done.


I'm trying to make up my mind on what temperature values I want for my thermal switches & here are my thoughts on this:

• If I keep the OEM sized thermostat in the truck (I believe this is a 195 F), I probably want a 195 on, 185 off for the Lo speed fan turn on & something around 200, or 205 on for the Hi speed fan turn on.
• If I change the thermostat to something lower, then I would also lower my thermal switch values - I see that a number of you have used the 180 F thermostat, how has that worked out (summer & winter)? Engine performance? E-test results?