Component Testing

1. Using a suitable ohmmeter, check thermo control switch, located on water inlet housing, as follows:
a. Check that no continuity is present when water temperature is below 177.8°F.
b. Ensure continuity exists when the coolant temperature is above 192.2°F.
c. If continuity checks are not as specified, replace switch.

Fig. 3 Checking Cooling Fan Motor Relay.:

Fig. 4 Checking Cooling Fan Motor Relay Operation.:

2. Using a suitable ohmmeter, check continuity exists between terminals 3 and 4, Fig. 3.
a. Using a suitable ohmmeter, ensure no continuity exists between terminals 1 and 3 and between terminals 1 and 4, Fig. 3.
b. Using a suitable ohmmeter ensure no continuity exists between terminals 2 and 3 and between the terminals 2 and 4, Fig. 3.
c. Apply battery voltage across terminals 1 and 2, Fig. 4 and ensure continuity exists between terminals 3 and 4.
d. If continuity checks are not as specified, replace relay.

Fig. 5 Checking Cooling Fan Motor.:

3. Using a suitable ammeter and battery, connect fan motor connector, Fig. 5. Ensure motor rotates smoothly and current draw is 5.5-8.5 amps.