I have my cooling system Fans powered right from the battery as that is what the DeRale PWM system instructions wanted. I had to go to the battery for my new EFI system as well so I ran a new #4 flexible cable from the battery and put a new fuse block under the passengers side dash for just the Cooling Fans and the EFI controller. The wires supplying the power are way oversized bringing the battery power up front to the new fuse block.

This is the 3rd PWM Controller I am on. The first was another brand and blew up the first time I used it. The second was a DeRale that just died randomly so I have a back-up like I described above. The DeRale system makes so much sense and works just as well as they designed it. The reduction of noise is enough reason for me to use the PWM type controllers. I am assuming that having a backup system ready for action that the DeRale will probably last forever. I have a 120 amp alternator and I hope that will be able to take care off the EFI system and the cooling fans along with the normal items.

The temperature sensor that you mount on the radiator mounts right above the Return connection where the hose take the cooler coolant back to the engine. It is measuring the coolant temperature where it is going back to the engine, not at the Input of the radiator like so many cooling fans use. The whole idea behind the DeRale PWM controller was for it to Hold your engine where you want it to run temperature wise. It has a small screw that you can adjust the point where it turn on. You set it for your ideal running temperature (for the engine) and leave it. When the temperature goes above the set-point it will speed up to compensate for the extra heat. When the temp drops the fans slow down and make less noise.

Merry Christmas to all!