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 available to suit the majority of vehicles that use a switch thread of M14 x 1.5. We also sell this item with an adapter to fit it into your top radiator hose in our eBay shop.
Ideal for use with our range of high powered fans featuring sizes from 7" to 16" and motors from 120W to 220W.
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 "coldest" switches would allow it to reach.
A good rule of thumb is that the on temperature of the switch should be around 12°C to 18°C higher than the vehicles rated thermostat opening temperature i.e. 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 86°C to 92°C so you would use the 90°C on switch. If your thermostat opens at 82°C you want an "on" temp of 94°C to 100°C so you would use the 95°C on switch.
Thermal switches available:
- 80°C on / 72°C off (± 3°C)
- 85°C on / 77°C off (± 3°C)
- 90°C on / 80°C off (± 3°C)
- 95°C on / 85°C off (± 3°C)
- 100°C on / 90°C off (± 3°C)
- 105°C on / 95°C off (± 3°C)
- 110°C on / 100°C off (± 3°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 you are replacing an existing OEM switch it is very likely it will already be wired through a relay and our switch can use the existing wiring, but please check before fitting.
For wiring we recommend running the fan directly from the battery via a relay and inline fuse, with the relay activated from a 12v + switched ignition source. You can also use a constant 12v source to activate the relay instead and this will allow the fans to continue running after the car is turned off until the coolant has reached the "off" temperature of the switch, as many modern cars do to aid with engine cooling after running.
The switch should be wired into the ground wire for the low current side of the relay. The switch is only suitable for up to around 1A of current draw, and most fans draw at least 5A of current, so wiring the switch directly inline with a fan will blow the switch.