Firebird V8-305 5.0L VIN F FI (1987)
Radiator Cooling Fan Motor: Description and Operation
On models equipped with electric engine cooling fans, the battery ground cable should be disconnected whenever underhood service is performed.
1985---87 PONTIAC FIREBIRD
SYSTEM DESCRIPTION
V6-173 VIN S & V8-305 VIN F
The cooling fan is controlled by a cooling fan relay whose coil is controlled by the redundant cooling fan switch and by the ECM which closes when
coolant temperature exceeds 228 degrees F. The relay is then energized and its contacts close to supply battery voltage to cooling fan.
V8-305 VIN G & VIN H
The cooling fan is controlled by a cooling fan relay whose coil is grounded by the cooling fan switch (which closes when coolant temperature is above
228 degrees F) and also through the A/C control head. The relay is then energized and its contacts close to supply battery voltage to cooling fan.
TROUBLESHOOTING
V6-173 VIN S & V8-305 VIN F
If cooling fan relay has failed, test redundant cooling fan switch for intermittent operation as follows:
1.
Warm up engine until cooling fan comes on.
2.
Disconnect connector from redundant cooling fan switch.
3.
Connect self-powered test lamp to switch and to ground. Test lamp should light steadily.
4.
If test lamp flickers at all, install new redundant cooling fan switch.
V8-305 VIN G & VIN H
If cooling fan relay has failed, test cooling fan switch for intermittent operation as follows:
1.
Warm up engine until cooling fan comes on.
2.
Disconnect connector from cooling fan switch.
3.
Connect self-powered test lamp to switch and to ground. Test lamp should light steadily.
4.
If test lamp flickers at all, install new cooling fan switch.
SYSTEM DIAGNOSIS
V6-173 VIN S & V8-305 VIN F
Fan Runs When Jumped; Does Not Operate In Normal Use
1.
Disconnect connectors from cooling fan relay (located at upper LH side of front of dash, V6-173 VIN S; RH side of radiator support, V8-305 VIN
F) and check voltage to ground at connectors with ignition switch in RUN. Battery voltage should be at terminal E, red wire, V6-173 VIN S;
orange wire V8-305 VIN F, and at terminal, C brown wire.
2.
If battery voltage is not available at terminals, check circuit that supplies terminal. If voltage is available, proceed to step 3.
3.
Reconnect connector to cooling fan relay. Disconnect dark green/white wire from redundant cooling fan switch (located rear of engine, near
distributor, V6-173 VIN S; lower RH rear of engine, V8-305 VIN F) . Connect fused jumper from wire to ground.
4.
With ignition switch in RUN, check that fan runs.
5.
If fan runs, relay and wiring are OK. Install new redundant cooling fan switch.
6.
If cooling fan does not run, check dark green/white wire to relay and black/red wire to fan. If wiring is OK, install new cooling fan relay.
V8-305 VIN G & VIN H
Fan Runs When Jumped; Does Not Run In Normal Use.
1.
Disconnect connectors from cooling fan relay (located on engine harness, LH front of dash) and measure voltage to ground at connectors with
ignition switch in RUN. Battery voltage should be available at terminal D, red wire, and terminal C, brown/white wire.
2.
If battery voltage is not available at terminal, check circuit that supplies terminal. If voltage is correct, proceed to step 3.
3.
Reconnect connector to cooling fan relay. Disconnect dark green wire from cooling fan switch (located at RH side of engine, above rear of starter
solenoid).
4.
Connect fused jumper wire from dark green wire to ground. With ignition switch in RUN, cooling fan should run and battery voltage should be
available at terminal D, red wire.
5.
If cooling fan runs, relay and wiring are OK. Cooling fan switch should be replaced.
6.
If cooling fan does not run, check dark green wire to relay and black/red wire to fan. If OK, install new cooling fan relay.
COOLING FAN, REPLACE
1.
Disconnect battery ground cable.
2.
Disconnect wiring from fan motor and frame.
3.
Remove fan assembly from radiator support.
4.
Reverse procedure to install.
