Our very own designed Digital Thermatic Fan Switch Kit can be used with our Thermatic Fans, EWP's and competitors Fans.

It senses air temperature as it passes through the radiator with the sensor placed in the radiator fin section or the sensor can also be placed directly into the coolant system in combination with a Temperature Sensor Adaptor Kit (Part 0409).

It can be used for 12 or 24 volt applications and has an adjustable temperature range of 40ºC to 110ºC (104ºF to 230ºF) which can show Centigrade or Fahrenheit. Temp is set by pressing the set button. It can run 1 or 2 fans. The second fan (if applicable) will start 10 seconds after Fan #1 runs. It operated thermally & also when the air conditioning is in operation. 














 *Note: The unit is Not WaterProof


 24 Volt Application 

Kit sold in 12 volt configuration, for 24 volt application, you will need to purchase 2 x 24 volt relays. 

Simply search for part 10534 in our search bar (top right-hand side of website).



It senses air temperature as it passes through the radiator and has an adjustable temperature range of 40ºC to 110ºC (104ºF to 230ºF).
The Temperature Sensor is placed in the radiator fin section as close to the hot coolant inlet as possible, no need to cut hoses or can be placed directly into the coolant system.

The 0444 sensor can now also be placed directly into the coolant system. To help you identify if your 0444 is capable of water / coolant applications, the sensor cable will be 1meter in length whilst the older 0444 units only have a 50cm cable. 

You will also need to use a Temperature Sensor Adaptor Kit (Part 0409) to assist with this type of fitment.

**NOTE: ensure you have a current 0409 which inlcudes a 5 & 6mm Olive. A Star Burst on the packaging will you identify this along with two olives in the packaging. You can also contact us directly to attain a 5mm olive should you have older stock (Part 10408).


  • Max voltage: 12 to 27V (For 24V, relays need to be changed, not supplied in kit)
  • Max currentRated to 30 amps per Fan (Maximum 40amp per Fan) Unit comes with 2 x 30 amp fuses and 2 x 40 amp relays
  • Relay setup: Dual relay
  • Speed: Single speed, 10 second delay to start up the second fan
  • Applications: Suitable for single and dual fan applications
  • Screen Display: LED digital temp display, actual temp + set temp
  • Temp Display: Centigrade or Fahrenheit
  • Temp settings: 40°c to 110°c  (104°F to 230°F)
  • Temp setting: Push Button
  • Circuit type: Pre-programmed micro controller
  • Output wires: Batt + Batt - IGN, AC Clutch, Fan #1, Fan #2 Thermistor Probe
  • Dimensions: 95x65x56 mm

*Note: if using this switch for use with our EWP's, it will not vary the speed of the pump in response to engine temperature but rather turn the pump on and off at your set temperature. For EWP control, we would recommend part number 8001 which can manage both the EWP and your Thermatic Fans.   

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Related Tech Tips

It sounds like it is constantly rebooting.

The cause is that you have wired the controller up incorrectly by wiring the ignition directly to the ignition coil and not an ignition switched source like accessories. To test simple wire the ignition directly to battery positive, if this solves the issue simply re-locate the ignition wire.

The reason that your having this issue is because the electronics of the switch draw power for the ignition wire so the voltage needs to be constant and stable.

The ignition coil is not always a constant voltage, and it pulses in relation to the ignition cycle (unsuppressed) meaning it is neither constant or stable.

This can also be the same or similar for the distribution block due to other loads on the system.

What is happening in your case is that the voltage is dropping and causing the unit to power down, this voltage drop happens every 3 seconds

You can always try running the ignition through a relay controlled by the distribution block to connect the unit to the battery. This should help filter the “noise” in the ignition wire

The probe from the 0444 can be used within the radiator fins measuring thermal air temperature or installed it into your water / coolant system.

PLEASE MAKE SURE you DO NOT cut the Sensor / Probe wiring to shorten or extend while installing. This action interferes with the resistance signal to the control box and subsequently an 'err' message will appear.

The switch will be completely useless and not serviceable if you cut the wiring.

We suggest you wind up the wiring should you need a shorter the lead.

Display behaviour



Err 1

Temp sensor short circuit

Replace unit

Err 2

Temp sensor open circuit

Replace unit

Constant incorrect reading of 120c or 248f

Temp sensor short circuit

Replace unit

Flashing display / unit


Might not operate correctly

Check ignition source location. If the ignition is connected to the coil or another similar source Must be constant +ve source.

Test by connecting to battery +ve as this will provide constant power. If direct battery connection solves issue, re-locate ignition wire to better location (preferably direct from ignition under dash)

Yes, you can use the A/C wire as a manual override by providing it with 12V from a switch.

There is a 10 second delay between fan 1 and fan 2, if the temperature is dropped to the shut off point in this time then fan 2 will not turn on for very long this is totally normal.

The #0444 is not designed to operate after the car is shut down, it can be wired in such a way to have it run for a period of time after the ignition is turned off but it requires added wiring and a time delay relay.

It is not necessary to run fans after engine shut off unless there is an electric pump providing coolant flow through the radiator otherwise you are simply cooling the same water/coolant in the radiator and it is not circulating.


The unit is powered by the ignition. To have the unit come on when the ignition is on (but engine not started) you need to connect the ignition wire of the unit to a positive source that is on when the ignition is on.

Do not wire the ignition line to any 12V source, if you connect the unit to the ignition coil, ECU/computer or any other load it will cause issues, like you’re having

I suggest wiring directly to the ignition source for the best results.

Part #0465 is designed to fully replace the temperature probe on the latest version of the Digital Thermatic® Fan Switch Kit - part #0444.

The new version has a bullet style connector in the temperature sensor wires that allows for the sensors to be swapped out if they get damaged, or changed to the threaded type.

If your unit has the bullet connector then you can simply pull the prob style sensor out and connect the #0465 into the connector.

If your unit does not have this connector then you will need to get part No. #0418 which is a brass fitting designed to hold the prob in the coolant.