How to Wire a Radiator Fan

  • 1-4 hours
  • Intermediate
  • 20-35
What You'll Need

Before understanding how to wire a radiator fan, it is important to understand the role that a radiator fan plays in a car. The car basically moves forward due to a mixture of air and fuel that is ignited by compressing and expanding the mix inside the cylinders. This generates a heat which in turn can cause damage to the engine. This is where the radiator comes into play and its job is to remove the heat from the engine. The radiator is a large matrix of small pipes. It cools the coolant as it passes through the radiator removing the heat that has accumulated in the engine. When the coolant reaches a temperature of 100 degrees Celsius, the computer in the car will turn the radiator fan on to further cool down the coolant. This helps in moving the heat from the engine to the radiator fins. As the air is moving at very high speeds over the radiator, this will cool down the liquid and the water pump will pump the coolant back in the engine.

Step 1: Connections

Unscrew the nut on the negative side of the battery and disconnect the cable. Install fan controller by drilling a hole for its mounting, and place as close to the battery as possible. Placement should be a maximum of 10 inches from the radiator.

Connect in-line fuse to the positive battery terminal.

Step 2: Wiring

Cut a wire, strip the insulation from both the ends and attach to the fan controller. The other end of the wire that was fitted to the in-line fuse needs to be fitted with a female spade terminal.

Step 3: Terminals

Connect the female blade terminal onto the fan controller marked B+. The black wire that comes attached to the fan controller attaches to a good ground. The female blade terminal attaches to the red wire on the fan. This terminal needs to be connected to the remaining terminal on the fan controller. A terminal needs to be attached to the black wire on the fan and ground to the frame.

Step 4: Temperature Bulb

Unroll the temperature bulb and line from the fan controller. The temperature bulb is inserted into the engine side of the radiator.

Step 5: Reconnection

Reconnect negative battery cable.

Now, you can start the engine and observe the temperature gauge to see that it is operating at normal temperature levels.