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

The sensor, a Temperature Probe (Air or Coolant Fitment) 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) which is available from our store.

Sensor Wire length:

  • 142cm in total (Wire from switch 112cm plus sensor connector 30cm)
  • Post 15-Dec-2021 = 320cm total (Wire from switch 290cm plus sensor connector 30cm)

*The sensor wire has been increased to 320cm from the 15-Dec-2021, batch date 2021

The switch can run 1 or 2 fans and be used for 12 or 24 volt applications. It has an adjustable temperature range of 40ºC to 110ºC (104ºF to 230ºF) which can show Centigrade or Fahrenheit.

  • Fan #1 will start once the temperature reaches the set temperature.
  • Fan #2 (if applicable) will start operation 10 seconds after fan #1 starts. 

The fan/s will operate until the temperature falls by 5°C below the set temperature.


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


IP66 Rated:

  • Protected from total dust ingress
  • Protected from high pressure water jets from any direction, limited ingress protection
  • Not waterproof

Integrated electrical noise filter for improved compatibility and reliability in older vehicles that produce high levels of electrical interference and noise.




Digital Fan Switch IP66


Thermal Sensor Probe 1
Mounting Kit for Thermal Sensor Probe 1
Red 6mm Ring Terminal 1
Blue 6mm Ring Terminal 1
Blue Wire Joiner 2
Self Tap Screw 2
Instructions 1
How to Install the Digital Thermatic® Fan Switch

















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 also be placed directly into the coolant system. You will need to use a Temperature Sensor Adaptor Kit (Part 0409) to assist with this type of fitment.

We also offer a Digital Thermatic® Fan Switch with 1/4" NPT Thermal Sensor Kit, part number 0445.



  • 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
  • Sensor Wire length: 142cm in total (Wire from switch 112cm plus sensor connector 30cm)
  • 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 8002 which can manage both the EWP and your Thermatic Fans.   

Optional Parts (sold separately)

¼ NPT THERMAL SENSOR ADAPTOR KIT SUITS #0444, 0445, 0500, 8002 (PART #0465)

The Davies, Craig ¼" NPT Thermal Sensor Adaptor Kit is designed to fit a ¼ NPT Sensor to Part Number 0444 or 0500 (Digital Thermatic® Fan Switch or Gauge). This will enable you to change the sensor type and fitment options from the 5mm diameter probe sensor provided in these kits as standard.



Suit Part Number 0444 - Digital Thermatic® Fan Switch Kit & 0500 - Digital Gauge Thermatic Fan & EWP Switch Kit.

It is a spare part for those customer who may have inadvertently damaged the sensor.

User Reviews

  • 0444 fan controller

    Replaced a derale unit that never worked properly. The davies craig is so simple to install and it works 100% adjustments for fan turn on are simple. Also turning 1 fan on at a time removes amp draw waiting 10sec to have fan #2 come on really helps the amp load at startup. Overall I'm impressed only thing id like is a higher amp unit for bigger fans a 50a breaker would help for my next project

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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.

You can extend the power wiring then relocate the switch to a location where you would like the sensor fitted.

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.