185°F Fan Switch for Mazda RX-7 FD Installation Guide
Share
The factory fan switch that Mazda used is supposed to turn on the fans around 210°F*. However, the over 30-year-old part often doesn’t work, either from a poor connection at the switch plug or because the old plastic part finally just gave up. As a result, it has become a commonly overlooked issue on 3rd generation models, and can frequently lead to overheating. If the engine overheats, it can potentially warp the metal and have catastrophic effects on its overall lifespan and functionality.
Our switch is a direct trigger for the cooling fan relays and works independently of the car's ECU, even with aftermarket computers, and the updated sensor easily replaces an allen plug located on the thermostat housing just below the engine coolant cap facing the right side of the car. It even fits all models 1992-2002!
Here's how to install it:
1. Within the engine bay, locate the allen plug just below the engine coolant cap facing right. Remove the allen plug, and then screw the switch into the exposed hole. Make sure to use RTV on the threads because Teflon tape can prevent it from grounding, in which case the fans will not properly activate.
2. Locate the original fan switch behind the thermostat housing just below the temperature sensor with the green plug. It isn't necessary to unplug it or remove it but you need to cut the wire, crimp it to the supplied spade connector, and then plug in your new sensor.
3. Before plugging the switch in, it's a good idea to test the system. With the ignition in the 'Run' position (without starting the engine), ground the old fan switch wire, and both fans should run. If they do not run, the cooling fans may need to be serviced.
Simple, quick, and easy!
Upgrade your Mazda RX-7 FD's longevity and cooling power
*This higher operating temperature is used purely to improve emissions for U.S. standards. However, the best engine longevity is achieved by maintaining cooler operating temperatures rather than appeasing the government.