Water Thermo Switch
- Disconnect water thermo switch single pin harness connector.
- Using ohmmeter, measure resistance between ground and water thermo switch terminal. See Fig 1. Resistance readings should be as follows:
- Coolant temperature is less than 109°F (43°C), resistance reading should be zero ohms
- Coolant temperature is more than 131°F (55°C), resistance reading should be infinite ohms
If either resistance reading is not as specified, replace water thermo switch. If resistance readings are as specified, reconnect water thermo switch single pin harness connector. Problem is intermittent.