I have an idea and want to know your thoughts on this...

I want to construct an automatic cooling fan circuit to overrride the stock settings of 212º and 226º.

Features: adjustable temp setting through the use of a potentiometer so you could tune in the desired temperature you'd want the fans to come on at (between a low setting of like 185º and then up to the point where this circuit wouldn't even be in use (and the PCM would take over at the stock settings). Pssible a main on'off switch so you could turn the whole thing off and let the PCM do it'* thing.

My thoughts on it. Wouldn't be hard or costly to build. It would allow the motor to cool down quicker even after the key is off, and would shut off automatically once the temp is down to the set point. Fans would run only from recieving the set input value from the the ECT sensor, so turning on and turing off would be completely automatic, no switch to worry about shutting off. I personally like the idea of the fan being able to run after the motor is shut down, and then shutting off automatically when cooled.

What do you all think? Am I wasting my time or what? This thing could be made for less than 20 bucks most likely. I just have to get with my professor to help me design the circuit. I am thinking of doing this because I want automatic control of the fan at a setting I WANT, without using a simple on'off override switch, becasue the override won't work after the key is off. I do TONS of city driving, car'* on and off frequently, and would like the sucker to stay cooler.

The closest thing to that I ever heard of is this:

http://www.zzperformance.com/zzp/pro...witch_hilo.htm

But you can't control what temp it starts at. That might require PCM reprogramming.