Cooling System: Testing and Inspection

FAN MOTOR, REPLACE

1. Disconnect battery ground cable.
2. Disconnect electrical connector from fan motor.
3. On models equipped with 4A-C engines, remove front grille. On all models, remove cooling fan assembly.
4. Remove attaching nut, then separate fan blade and spacer from motor.
5. Remove bushings and attaching screws, then separate fan motor from shroud.
6. Reverse procedure to assemble and install.

TROUBLESHOOTING

1. If coolant temperature is low (below 181°F), proceed as follows:
a. Turn ignition switch on and ensure cooling fan is not operating.
b. If fan is operating, a faulty fan relay and/or temperature switch is indicated. Check for separated electrical connectors or severed wire between relay and temperature switch.
c. Disconnect temperature switch wire, then check that fan rotates.
d. If fan does not rotate, check fan relay, fan motor, ignition relay and temperature switch.
e. Connect temperature switch wire.
2. If coolant temperature is high (above 194°F), proceed as follows:
a. Raise engine temperature to above 194°F, then check that fan rotates.
b. If fan does not rotate, replace temperature switch.

COMPONENT INSPECTION

1. Using a suitable ohmmeter, check temperature switch, located at radiator lower tank, for continuity. No continuity should exist when water temperature is above 194°F. Continuity should exist when water temperature is below 181°F.

Fig. 3 Checking ignition switch relay. 1984-86 Corolla FWD models:

2. On 1982-86 models, inspect ignition switch relay, located in engine compartment relay box as follows:
a. Measure resistance between terminals 1 and 2, using a suitable ohmmeter, Fig. 3. Resistance should be 50-80 ohms.
b. Connect a 12 volt source across terminals 1 and 2, then check that continuity exists between terminals 3 and 4.
c. No continuity should exist between terminals 4 and 5.
d. If ignition switch relay does not check as specified, replace switch.

Fig. 1 Checking Cooling Fan Motor Relay:

3. On 1982-86 models, check fan motor relay, located in engine compartment relay box as follows:
a. Using a suitable ohmmeter, measure resistance between terminals 1 and 2, Fig. 1. Resistance should be 50-80 ohms.
b. Connect a 12 volt source between terminals 1 and 2, then using a suitable ohmmeter, check that continuity exists between terminals 3 and 4.
c. If fan motor relay does not perform as indicated in steps a and b, replace relay.

Fig. 2 Checking fan motor:

4. Connect a suitable ammeter and battery to fan motor connector, Fig. 2. Ensure motor rotates smoothly and current is 3.2-4.4 amps.