The 12v circuit provided turn on by an open collector signal.
Can somebody modify the circuit if I want to operate it with a toggle switch if the open collector signal pin is not activated?
Please provide the circuit.

 

Connect a single-pole, single-throw switch from the OPEN COLLECTOR input to GND.
That way either the open collector signal or the switch can turn on the fans.

I can't draw you a schematic, as I'm on a WebTV type thing and have no drawing tools availabie.

 

sajelectric,

I believe this is what SgtWookie is talking about.

williamj