What does the thermo time switch do?

1971 1.7 d-jet

Is this the cold start injector sensor?

Located below the cold start injector sensor.

I believe it is the sensor for the cold start injector.

The sensor on D-jet in '71 was a thermoswitch. If the temp was low enough it would supply ground to the cold start valve which would spray as long as the starter was engaged. Later they went to a thermo-time switch which would cut the ground to the CSV after cranking for around 10 seconds. This was to prevent flooding on engines wouldn't start.