Electronic controllers are much more than just a relay for your electric fans. They turn the electric fans on and off, most of them provide the ability to adjust the temperature at which the fans turn on and almost all of them take the place of relays.

Here’s a breakdown of what each of our controllers do so you can choose the one that’s best for you…:

Flex-a-lite offers part number 31147 which is an Adjustable Temperature Sensor. In addition to acting as a relay, it lets you vary the temperature at which the fan or fans turn on from approximately 180-240 degrees Fahrenheit with a simple knob. It uses a stainless steel probe that inserts in the radiator fins to sense engine-coolant temperature. This module is rated to manage 20-amps at fan start-up. The Cooling Control Module is ideally suited for many single fans. Reading the temperature from the fins is a much more desirable solution compared to plumbing into the coolant lines.

A Variable Speed Controller also acts as a relay and lets you vary the temperature at which the fan or fans turn. Additionally, it sets the fan speed from 60-100 percent, depending on the coolant temperature. This reduces the electrical load when the fans first start, and only draws the amperage needed for the temperature of the engine coolant. This controller also keeps the fan or fans running for 30 seconds after the key is turned off. This module is rated to manage more amperage than the Cooling Control Module; 45-amps at fan start-up. There are several part numbers available:

Part # 31163: Variable Speed Control with the threaded sensor

Part # 31165: Variable Speed Control with the stainless steel temperature probe

The Variable Speed Controllers can be used with any electric fan; single or dual.

Additionally, we offer two versions of the Variable Speed Controllers with a feature that known as Quick Start: They start the fans at 100 percent power instead of varying the power to the fans between 60-100 percent.

Part # 31173: Variable Speed Control — Quick Start with the threaded sensor

Part # 31174: Variable Speed Control — Quick Start with the stainless steel temperature probe

Part # 31148 Auxiliary Switch lets you control or override the electric fan function. This switch can be wired to turn on a fan regardless of the engine temperature (overriding the temperature control feature in the controller) or it can be wired to turn the electric fan off (useful for drag racing or water crossings during off-roading). The switch has a 10-amp rating, and it can be used with any of the above controllers.