Temperature sensor from rear of engine, MX-5 1.6 mk1 1989-1993.
It lives down the back of the engine and the coil pack needs to be moved out of the way to get access to it.
This is the sensor that tells the ECU the coolant temperature so that it can turn the choke on if required. If this is playing up it will usually trigger an ECU fault code '09'.
NM00156.
