The Mechanical Thermatic® Fan Switch & Relay (12V & 24V) for Air Conditioning can be used with our Thermatic Fans & EWP's. It senses the coolant temperature after it passes through the engine block prior to entering the radiator and is adjustable from 40° to 100°C (104° to 212°F). The Thermal Switch is mounted near the radiator and the stainless steel probe fitted inside the radiator hose. The Thermal Switch & relay kit enables a fan to operate both thermally and also when the air conditioning is running.


24 Volt Application: 

Kit sold in 12 volt configuration, for 24 volt application, you will need to purchase 24 volt relay for each electric fan. 

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








Thermal Switch


  Temperature Range 40° to 100°C (104° to 212°F)
Rubber Seal Suits 1mm Capillary


  Lead Length 100cm
Thermal Switch Knob


  Sensor Probe Size Suites 6mm Olive
3M White Scotch lock Terminal


Relay - 12V 40 Amp



Wiring Harness - Fan 12 & 24V







Should you not want to squeeze the probe of the Mechanical Thermatic® Switch between the radiator inlet and radiator hose, or the radiator fins, we recommend you look at part number 0409 or 0400. (Sold Separately)


The #0409 is a simple, economical Adaptor Kit allows easy fitting directly into the top radiator hose. Just fit the probe into the compression fitting, remove about 17mm (2/3”) of radiator hose, fit the adaptor between each hose and secure the hose clamps. The kit comes complete, as shown, for a watertight and effective probe installation. Extra rubber sleeves are supplied to enable fitment to radiator hose sizes from 32mm to 40mm (1¼” to 1½”) diameter. Suits all temperature sensors with either a 5mm (3/16”) or a 6mm (1/4” outside diameter and temperature gauge senders with 6mm
(1/4”) NPT thread. Note: This is an accessory for use with #0401, #0404, #0444 and
#0455 Thermatic® Switches.


Davies, Craig offers three types of Thermatic® Fan Switches

  • Part #0444 senses air temperature near the top radiator hose as it passes through the radiator or senses coolant temperature (with #0409) for single or twin fan operation.
  • Part #0455 Premium Thermatic Switch senses both air or coolant temperatures (with #0409), single or twin fan operation, attractive dashboard mounted monitor.
  • Part #0401 senses the coolant temperature after it passes through the engine block prior to entering the radiator.
  • Part #0400 is a combination of the unit #0401 (opposite) and the #0409 Hose Adaptor (opposite), offering probe placement in the top radiator hose.


 *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 the LCD Controller part number 8002 which can manage both the EWP and your Thermatic Fans. 

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