Thermo switch pic and question

[fairwynds]

Hi
was tinkering and broke this wire. Im sure its the one that goes to the blue spade connection, based on the fact its a) right length to reach and b) the spade is 'empty'!
Just looking in Haynes and it talks about the big brass nut thing (not in THOSE words!) being a thermoswitch, for manifold?
Can anyone give me a laymans explaination of this brass thing please? What it does, and why are there two plugs going into it?
Very much appreciated, as my knowledge of electrikkery can be written on a postage stamp!

(ps - I foolishly looked at the back of the Haynes manual at 'wiring diagrams'....now my head hurts!)

Thanks again... FW

[bigherb]

Looks like a Lilac/Black wire which indeed connects to the thermoswitch.
The thermoswitch is a coolant temperature dependant switch. When the engine is cold the switch is closed allowing the 12v feed from the black wire across to the Lilac/black wire which switches on the relay for the electrical manifold heater and the carburettor part throttle heater. As the coolant warms up the switch opens disconnecting the power to the relay switching off the heaters.

[fairwynds]

ahhh, thankyou - I think that makes sense