Thermo Time Switch: Testing and Inspection
When engine temperature is below approximately 113°F (45°C), current is allowed to flow for a certain period (temperature dependent) while starter motor is running.
1. Check that switch closes when engine is started by connecting a test lamp in series across terminals of cold start connector. It is not possible to make a more accurate check of the cut-in time or temperature. If the integrity of the thermo-time switch is in question, install a new thermo-time switch.