Its down underneath the inlet manifold.

Follow the hard plastic pipe from the throttle housing and you will see it.

It has an internal heater which warms a bi-metallic strip and closes up over a period of about 2 minutes to allow a little more air into the engine while its stone cold.

Check the wiring plug is connected and you could remove it and check to see if it closes up with 12v across its terminals although they can be a pain to remove.