Assignment

When control units were scarce, yet the vehicle featured an auxiliary injector, the injector was controlled via a thermo time switch and the current on board.

Function

Actually, it has three connections if you count ground, too. Two connections are responsible for heating a bimetal. Via the third connection (ground) the current is switched to the cold start valve. From a certain temperature of the coolant onward the injector is anyway switched off. The lower the temperature, the longer it takes to heat the bimetal and to disconnect its contact.