You will need a relay or a heavy-duty switch because the fan will draw a lot of power. I have a sensor in the coolant (intake manifold) that turns my fan on. The sensor circuit is basically from the ignition switch to the relay, from the relay to the sensor. There is a separate, much heavier wire from the battery, through a fuse or circuit breaker (probably 30 amp), to the relay, and from the relay to the fan motor, the other lead on the fan motor goes to ground.

When the sensor completes the circuit from the ignition switched power to ground that turns on the relay which connects the fan to the battery.

Your fan may be wired as a puller (standard arrangement) so you may need to reverse the rotation to make it a pusher. Best way to test is just wire the fan to a battery and see which way the air flows. If it flows the wrong way try reversing the positive and negative connections.

 

I run all the cars I do to run all the time through a relay.. And as a puller as much as I can..I try my best to never use a pusher fan..

 

If you wire the fan to run the opposite direction, I think you also need to remove the blade and flip it over to get the best air flow. It doesn't move air very well running backwards.

John

 

Sensor and switch

I have a roadster with an SBC and a puller fan. I use a sensor and I have a dashboard switch, just in case.

 

if you're using it as a pusher DO NOT run the shroud.

 

Diode

Sometimes you need a diode in the circuit. The fan can spin and act as a generator putting out power into a circuit when you don't want it.

 

Sometimes you need a diode in the circuit. The fan can spin and act as a generator putting out power into a circuit when you don't want it.

Never seen that happen..:drunk:

 

It's a pusher and I have to keep shroud it's part of the assemble.

 

Well then expect problems on the highway.

 

Next time you're at the bone yard, try to find a car with a factory pusher fan.

 

Here is one of the best ways to run wiring for radiator fans. Check out the attachment. Be Cool's kit has everything you need to wire up your fan. http://www.summitracing.com/parts/bci-75021/overview/

 

$85 for what I can buy on ebay for $8?! Just think- there's some poor schmuck that bought that too...