scotm

Pin Connections for the Maplin N17AW relay: Relay Coil Pin 1 - Ignition Feed Pin 16 - Coolant Sensor (The coolant sensor then goes to earth) Relay Contacts: Pin 4 - Ignition Feed Pin 6 - Warning Light (Then warning light goes to earth) (You can also use pins 13,11 instead of 4,6) There is a pdf datasheet on the maplin website with the pin details N17AW Relay Hope this helps

As longterm lurker when i saw this response I had to register and reply. I have just fitted one to my defender and got it working successfully (eventually). I followed the ep90.com instructions but couldn't get the light to work when connected through the sensor. After consulting a friendly electronics hobbyist we came to the conclusion that the relay recommended on ep90 required more current than could flow through the sensors reed switch. I changed the relay for a 12v telecoms one (these have much higher coil resistance so need less current) from Maplin part number N17AW and bingo it worked. (This relay requires soldering at the terminals) RSS do similar relays part numbers 422-7079 and FP2-D3002.