Diesel Data: Automotive Repair

Radiator Cooling Fan Motor Relay: Testing and Inspection

COOLING FAN RELAY
INSPECTION





1. INSPECT NO. 1 COOLING FAN RELAY
a) Remove the relay box cover.
b) Remove the No. 1 cooling fan relay. (Marking: FAN NO. 1)





c) Inspect the No. 1 cooling fan relay continuity.
1) Using an ohmmeter, check that continuity exists between terminals 1 and 2.
If no continuity exists, replace the relay.
2) Check that no continuity exists between terminals 3 and 5.
If continuity exists, replace the relay.





d) Inspect the No. 1 cooling fan relay operation.
1) Apply battery voltage across terminals 1 and 2.
2) Using an ohmmeter, check that continuity exists between terminals 3 and 5.
If no continuity exists, replace the relay.
e) Reinstall the No. 1 cooling fan relay.
f) Reinstall the relay box cover.





2. INSPECT NO. 2 COOLING FAN RELAY
a) Remove the relay box cover.
b) Remove the No. 2 cooling fan relay. (Marking: FAN NO. 2)





c) Inspect the No. 2 cooling fan relay continuity.
1) Using an ohmmeter, check that continuity exists between terminals 1 and 2.
If no continuity exists, replace the relay.
2) Check that continuity exists between terminals 3 and 4.
If no continuity exists, replace the relay.
3) Check that no continuity exists between terminals 3 and 5.
If continuity exists, replace the relay.





d) Inspect the No. 2 cooling fan relay operation.
1) Apply battery voltage across terminals 1 and 2.
2) Using an ohmmeter, check that no continuity exists between terminals 3 and 4.
If continuity exists, replace the relay.
3) Using an ohmmeter, check that continuity exists between terminals 3 and 5.
If no continuity exists, replace the relay.
e) Reinstall the No. 2 cooling fan relay.
f) Reinstall the relay box cover.