Float Switch
1. Connect wire to bulkhead earth/ground
One of the 2 wires on the float switch sensor you connect to earth/ground (there is a earth/ground connection on the bulkhead behind the coolant header tank on LHD cars).
2. Connect wire to buzzer earth/ground
The other wire on the float switch sensor you connect to the earth/ground wire of the buzzer/ led light.
3. Connect positive/12V wire
The positive/12v wire on the buzzer/led light you connect to the green/white wire on the connecter of the standard temperature gauge (on the back of the instrument cluster) OR you can choose a 12v ignition feed of choice.
See picture attached of the LED in the instrument cluster.