Thermo Time Switch: Testing and Inspection

1. Remove cold start thermoswitch from engine block, and plug hole to prevent loss of engine coolant.

2. Place threaded portion of switch into ice water.

3. When switch is cold, check for continuity between electrical terminals and the metal body of switch (ground).

^ Both terminals should have continuity to ground (slight resistance may be present).

4. Place threaded portion of switch into hot water.

5. When switch is warmed, check again for continuity between electrical terminals and the metal body of switch.

^ Only one of the terminals should have continuity to ground when switch is warm. The terminal that connects to the Black/Orange wire (to the cold start valve) should have no continuity.

If switch does not operate as described, replace it.