If you have pusher fans, along with a hefty puller fan, you know the pushers don't really do much other than look cool. All my fans come on when the thermostatic switch in the lower radiator hose hits its point, because both the pushers and pullers are all wired together. The same is true with the toggle switch on the dash -- they all come on together with the toggle switch override. Plus, they are all handled by the same single relay. If you're stuck in traffic on a 100 degree day you do want all the fans on together, but for the most part, you only want your puller coming on. If the puller fan failed, the pushers would probably get you by. So, it only makes sense to modify the installation to get backup redundancy. After thinking it through, I decided I wanted the thermostatic switch to only turn on the puller fan, but I wanted the toggle switch to turn on all the fans. Plus, I wanted the pusher fans on a completely different circuit so if the puller's relay failed the toggle switch would still allow the pushers to come on. The hardest part was finding the 12v DPST-NO Relay that would handle the amperage of the pusher fans. Omron Part #G7L-2A-BUBJ-CB-DC12 fit the bill, and it easily mounts on the driver's foot box, up near the firewall, next to the voltage regulator -- almost invisible. Then all you do is cut the blue wire on the fan relay that leads to the toggle switch, cut the red wire to the pusher fans, and wire it all in. Here are some shots and a wiring diagram.
