Thermo Time Switch: Description and Operation

This switch regulates operation of the cold start injector by varying operating time according to engine temperature and length of starting cycle.
The switch is controlled by a bi-metallic spring surrounded with a heating coil. When the engine is cold, the contacts are closed and current flows to the cold start injector when starting the engine. Current flowing through the heating coil causes the bi-metal spring to bend, opening the contacts and deactivating the switch.
Cycle time for this operation is directly related to engine temperature. The warmer the coolant the shorter the injection time.