Well my car came from the factory with the single fan, and I just purchased a dual fan setup. My connector plugs right into either one of the two fans. Now do I just run another connector to the other fan in parallel, and have them come on at the same time, or should I run one to a toggle switch. I am really leaning toward the parallel setup, but am a little worried about how much amperage this will pull as opposed to my single fan setup, as I don't want to burn up any wires. When the factory put in this dual fan setup do both fans come on together or are they controlled by different things? It seems to me that if I get both fans to activate at the same time my cooling capacity should be increased over my factory single fan setup. I would love to hear what you guys think about this.

Thanks Dave

 

Dave,

Our single-fan cars have a single relay to control ONE 150W fan motor. Dual fan cars have a relay for each fan motor. The primary fan is controlled just like the single fan installation - the ECM determines when to operate the fan with a parallel connection from the AC high-side pressure switch.

The secondary fan is controlled by a coolant temerature switch installed in the right cylinder head. The switch grounds the fan relay coil (just like the ECM does on the primary fan) at about 230°F coolant temperature. You can install a second relay and temperature switch in the hole in your right head, or install a second relay controlled by a manual switch or the primary fan power.

Another option would be to purchase a fan control from Derale for about $40.00 that includes a relay and temperature sensor that attaches to the radiator. You can adjust the sensor to turn on at nearly any point, so you can use this as the primary fan and allow the ECM to control the other fan as a secondary unit. This works very well with a cooler thermostat, since the set point can be closer to the thermostat value than the factory ECM setting of 223°F. In this case, I would use the 150W fan as the primary and the 100W fan as the secondary.

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Later,
Vader
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"Make Me Bad"
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