M14 x 1.5 Thermal Radiator Fan Switch

(Inc. VAT)
(Ex. VAT)
*** International customers (incl. Channel Islands) will only pay the ex. VAT price, but customs charges may be payable to your country on import. Click here for more info.
(6 reviews) Write a Review
0.06 KGS

The Stoney Racing Radiator Fan Thermal Switch allows you to thermally control any aftermarket universal radiator fan. Perfect for kit cars or older vehicles that don't use electric fans as standard.

The switch actives when the sensor reaches the "on" temperature and turns off when it drops back below the "off" temperature. With seven different temperature ranges available we have a switch to suit the majority of vehicles.

We also sell various thread adapters to fit this item to an M16, M18, M22, 3/8" NPT or 1/2" NPT threaded hole, or an aluminium Hose Adapter to fit into your top radiator hose, all available in our store.

Ideal for use with our range of high powered fans featuring sizes from 7" to 16" and motors from 80W to 160W.

What Switch Temperature Do I Need?

This varies from vehicle to vehicle and colder is not necessarily better as the ideal operating temperature range for an engine may be higher than our lowest switch range would allow it to reach.

If possible you should find out the ideal operating temperature of your vehicle and choose a switch that turns on around 5deg. C higher than this ideal operating temperature.

If you cannot find your vehicle's ideal operating temperature you can also estimate by the vehicles thermostat temperature. Assuming the switch will be fitted in the hot side of the coolant system (before coolant passes through the radiator core) the on temperature of the switch should be around 10°C to 15°C higher than the vehicles rated thermostat opening temperature (the temp the thermostat begins to open at).

So for example if your thermostat starts opening at 74°C you want an "on" temp of 84°C to 89°C so you would use the 85°C on switch. If your thermostat opens at 82°C you want an "on" temp of 92°C to 97°C so you would use the 95°C on switch.

Thermal switches available:

  • 80°C (176°F) on / 72°C (162°F) off (± 2°C)
  • 85°C (185°F) on / 77°C (171°F) off (± 2°C)
  • 90°C (194°F) on / 80°C (176°F) off (± 2°C)
  • 95°C (203°F) on / 85°C (185°F) off (± 2°C)
  • 100°C (212°F) on / 90°C (194°F) off (± 2°C)
  • 105°C (221°F) on / 95°C (203°F) off (± 2°C)
  • 110°C (230°F) on / 100°C (212°F) off (± 2°C)


Important: The switch must be installed in the low current side of a relay (i.e. one of the wires to pins 85/86 on a standard 4 or 5pin relay). If the current exceeds 1 Amp the switch is likely to fail and this is not covered under warranty. Using the switch directly in the wiring to a fan will cause the switch to fail.

For wiring we recommend running the fan directly from the battery via a relay and inline fuse, with the relay activated from a 12v source, using either an ignition live source so the fans only run when the engine is running, or a constant 12v source which will allow the fans to continue running with the ignition off, as many modern cars do to aid with engine bay cooling after running.

The switch should be wired into the ground wire for the low current side of the relay. The maximum current rating of the switch is 1 Amp so fitting any fan inline with the switch will cause it to fail.


  • Fitment: Universal 12V
  • Construction: Brass, Plastic
  • Max Current Rating: 1 Amp
  • Operating Temperature range: -30°c to 200°c
  • Warranty: 1 Year (UK based)

6 Reviews Hide Reviews Show Reviews

  • 5
    M14x1.5 Thermo fan switch

    Posted by Jake on 24th Apr 2023

    Itam came in good time and works well

  • 5
    Thermal switch M14 1,5

    Posted by Per Bjoringer on 24th Aug 2022

    As expected and more - it was golden!

  • 5
    Thermal radiator switch

    Posted by Nigel on 16th May 2022

    arrived really quickly. exactly as described. easily fitted. works perfectly.

  • 5
    fan control

    Posted by Tom on 26th Apr 2021

    Fast delivery and did the job

  • 5
    M14 x 1.5 Thermal Radiator Fan Switch

    Posted by George on 10th Feb 2021

    best seller, very good parts