Radiator Cooling Fan System Test

NOTE: On A/C equipped models, an A/C high-pressure switch may be used in conjunction with cooling fan relays for controlling of radiator cooling fan. See the ENGINE COOLING FAN article in the ENGINE COOLING section for additional information.

Ensure engine coolant temperature is less than specified STEP 1 temperature. See RADIATOR COOLING FAN SYSTEM TESTING TEMPERATURE SPECIFICATIONS table. Turn ignition on. Ensure radiator cooling fan stops.
If radiator cooling fan stops, proceed to step 5). If radiator cooling fan operates, check cooling fan relay No. 1 and Engine Coolant Temperature (ECT) switch. See COOLING FAN RELAY NO. 1 and ENGINE COOLANT TEMPERATURE (ECT) SWITCH under COMPONENT TESTING.
If cooling fan relay No. 1 and ECT switch are okay, check for open circuit in wire between ECT switch and cooling fan relay No. 1. Consult appropriate wiring diagram if necessary. See WIRING DIAGRAMS.
Cooling fan relay No. 1 is located in fuse/relay box. See Fig 1. For ECT switch locations, see ECT SWITCH LOCATIONS table.
With ignition on, disconnect electrical connector at Engine Coolant Temperature (ECT) switch. For ECT switch locations, see ECT SWITCH LOCATIONS table. Ensure radiator cooling fan operates.
If radiator cooling fan operates, proceed to step 9). If radiator cooling fan does not operate, check cooling fan relay No. 1, radiator cooling fan, engine or fan main relay and necessary fuses.
Consult appropriate wiring diagram for proper fuse applications. See WIRING DIAGRAMS. See COOLING FAN RELAY NO. 1, RADIATOR COOLING FAN, FAN MAIN RELAY and ENGINE MAIN RELAY under COMPONENT TESTING.
If all components are okay, check for short circuit in wire between cooling fan relay No. 1 and ECT switch. Consult appropriate wiring diagram if necessary. See WIRING DIAGRAMS.
Install electrical connector on ECT switch. Start engine. Warm engine until coolant temperature is greater than specified STEP 2 temperature. See RADIATOR COOLING FAN SYSTEM TESTING TEMPERATURE SPECIFICATIONS table.
Ensure radiator cooling fan operates. Replace ECT switch if radiator cooling fan fails to operate and recheck operation.

RADIATOR COOLING FAN SYSTEM TESTING TEMPERATURE SPECIFICATIONS

Application	Step 1 Temp. °F (°C)	Step 2 Temp. °F (°C)
Tercel	181 (83)	201 (94)

ECT SWITCH LOCATIONS

Application

⁽¹⁾ Switch Location

Tercel

⁽²⁾

⁽¹⁾	For additional information on ECT switch locations, see Fig 1.

⁽²⁾	ECT switch is located in coolant housing below distributor and contains a single-pin connector with a Light Green wire.

Fig 1: Identifying Radiator Cooling Fan & Components