Diesel Data: Automotive Repair

Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection


1. Drain coolant and remove thermo switch.
2. Cool thermo switch to below 109°F and check that switch has continuity.
3. Heat switch to above 131°F and check that there is no continuity.
4. Apply liquid sealer to threads of switch and reinstall it, then refill radiator with coolant.