Radiator Fan Constantly On
toyride90
08-07-2013, 06:25 AM
I have a 1990 Toyota Corolla and the Radiator fan comes on when the car is started and it does not turn off until engine is turned off :jerking:
Brian R.
08-07-2013, 07:12 AM
Check the cooling fan relays and water temperature switch, and check for a separated connector or severed wire between the cooling fan relay and water temperature switch.
Water Temperature Switch - on water inlet housing.
(a) Using an ohmmeter, check that there is no continuity between the terminal and body when the coolant temperature is above 93°C (199°F).
(b) Check that there is continuity between the terminal and body when the coolant temperature is below 83°C (181 °F).
If continuity is not as specified, replace the switch.
Cooling Fan Relay (”FAN NO.1 ”) - in box by battery
A. Inspect relay continuity
Terminals 1 and 2 are horizontal pointing at one another.
Terminals 3 and 4 are parallel to each other pointing at terminals 1 and 2.
(a) Using an ohmmeter, check that there is continuity between terminals 1 and 2.
(b) Check that there is continuity between terminals 3 and 4.
If continuity is not as specified, replace the relay.
Water Temperature Switch - on water inlet housing.
(a) Using an ohmmeter, check that there is no continuity between the terminal and body when the coolant temperature is above 93°C (199°F).
(b) Check that there is continuity between the terminal and body when the coolant temperature is below 83°C (181 °F).
If continuity is not as specified, replace the switch.
Cooling Fan Relay (”FAN NO.1 ”) - in box by battery
A. Inspect relay continuity
Terminals 1 and 2 are horizontal pointing at one another.
Terminals 3 and 4 are parallel to each other pointing at terminals 1 and 2.
(a) Using an ohmmeter, check that there is continuity between terminals 1 and 2.
(b) Check that there is continuity between terminals 3 and 4.
If continuity is not as specified, replace the relay.
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