Seville V8-300 4.9L (1991)
Radiator Cooling Fan Motor: Component Tests and General Diagnostics
Refer To SCHEMATIC DIAGRAMS/ELECTRICAL AND ELECTRONIC DIAGRAMS, for wiring schematics when performing diagnostic
procedures on these systems.
Both Coolant Fans Do Not Operate At All
1.
If horn operate, proceed to step 2. If horns do not operate, check the following:
a. Check fusible link L for an open.
b. Check circuits 2, 532 and 533 for a short to ground before replacing fusible link.
c. Check circuit 2 to S160 and circuit 804 between S112 and G100 for an open.
2.
Measure voltage between underhood relay center position B terminal 2 to ground with the relay removed and ignition switch in RUN position. If
battery voltage is not present, check circuit 850 and coolant fan fuse 1 for an open.
3.
If battery voltage is present, check wiring to both coolant fans and the fan terminal contacts. If wiring or terminal contact is unsatisfactory,
repair/replace as necessary.
4.
If wiring and terminal contacts are satisfactory, check circuits 535 and 536 for an open. If both circuits are satisfactory, problem is ECM related.
5.
If one or both circuits are unsatisfactory, repair/replace as necessary.
No Low Speed, No High Speed Pusher Fan
1.
Disconnect coolant fan relay B from the underhood relay center. Turn ignition switch in RUN position and measure voltage between terminal 1
and ground then terminal 2 and ground of the relay center position B. If zero volts is present at one or both terminals, check circuits 2 and/or 850
for an open.
2.
If battery voltage is present, enter diagnostics and select ECM override ES08 as outlined under DIAGNOSIS set the display to 10. Connect a test
lamp between terminals 2 and 5 at position B of the relay center. If test lamps does not light, check circuit 535 for an open or short to battery
voltage. If wiring is satisfactory, problem is ECM related.
3.
If test lamps lights, connect a fused jumper between terminals 1 and 4 at position B of relay center. If coolant fan runs at low speed, check or
replace coolant fan relay B.
4.
If the coolant fan does not run at high speed, leave jumper in place and disconnect coolant fan relay C. If coolant fan runs at high speed,
check/replace relay C.
5.
If pusher fan does not run at high speed, check circuits 532 and 533 for an open to pusher fan. Also check pusher fan terminal contact. If
satisfactory, replace pusher fan.
No High Speed Pusher Fan
1.
Disconnect coolant relay C from the underhood relay center and with the ignition switch in RUN position, measure voltage between terminals 2
and 4.
2.
If battery voltage is present, check terminal contact at relay C. If satisfactory, replace coolant fan relay C.
3.
If zero volts is present, check circuit 804 for an open.
No High Speed Puller Fan
1.
Disconnect coolant fan relay D from the underhood relay center. With the ignition switch in RUN position, measure voltage between terminal 1
and ground then between terminal 2 and ground of the relay center position D. If battery voltage is not present at one or both terminals, check
circuits 2 and 850 for an open.
2.
If battery voltage is present at both terminals, enter diagnostics and select ECM override ES08 and set display to 01. Connect a test lamp between
terminals 2 and 5 of the relay center position D. If lamp does not light, check circuit 536 for an open.
3.
If test lamp lights, connect a fused jumper between terminals 1 and 4 of the relay center position D. If puller fan does not run, check circuit 533 for
an open.
4.
If the puller fan runs at high speed, check terminal contact at relay D. If satisfactory, replace coolant fan relay D.
No High Speed Both Fans
1.
Disconnect coolant fan relays C and D. Turn ignition switch to RUN position, measure voltage between terminal 2 and ground at position C then
between terminals 2 and 1 at position D. If battery voltage is not present at one or both terminals, check associated circuit for an open.
2.
If battery voltage is present at both terminals, check circuit 536 for an open or short to battery voltage. If circuit 536 is satisfactory, problem is
ECM related.
3.
If circuit 635 is not satisfactory, repair/replace as necessary.
