Toyota Water Temp Switch Bung
Want to run electric fans on your aftermarket radiator? This weld-in bung lets you use a genuine OEM Toyota water temperature switch to switch them on and off.
Why use an OEM Toyota switch?
Most aftermarket fan switches are built cheaply. They have loose spade terminals, no protection against water or dirt, and often rely on the radiator body for their ground. That ground doesn’t work when the radiator sits in rubber mounts. The Toyota switch has a sealed plug and a proper O-ring seal, so it’s simply more reliable.
Easy and clean to fit
Weld the bung into your radiator, water neck or radiator pipe and screw in the switch. A chamfer inside the bung guides the O-ring into place, so you get a watertight seal every time. Then connect the switch to a relay to run your fans.
Order it your way
Buy the bung on its own, or add an OEM Toyota switch. Each switch comes with the terminal pins and wire seals you need to wire it up.
- Normally closed switch (recommended). If a wire breaks or the plug is left off, your fans keep running. That way a fault can’t quietly overheat your engine.
- Normally open switch. This is the simplest wiring, but if something gets disconnected, the fans won’t come on.
Good for electric fan conversions (for example on a Supra), custom radiators, and cars that never came with a fan.
Want to know more? Check out our video below for an in-depth explanation.
