Cutlass Ciera V6-231 3.8L (1985)
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 BUICK CENTURY & OLDSMOBILE CUTLASS CIERA
System Description
The cooling fan is controlled by a cooling fan relay whose coil is grounded by the cooling fan switch when coolant temperature exceeds 228 degrees
F. The cooling fan relay is energized and its contacts close to supply battery voltage to cooling fan. The cooling fan delay relay operates cooling fan for
short time after engine is turned off. A solid state timer removes ground from cooling fan delay relay coil to switch off cooling fan.
V6-231 VIN 3
Three types of cooling fans are used with V6-231 VIN 3 engines:
a.
Single speed.
b.
Two speed (internal resistor).
c.
Heavy Duty Two Speed (external resistor).
On vehicles with single speed cooling fans, cooling fan relay coil is grounded through cooling fan switch. At coolant temperatures exceeding 228
degrees F, switch contacts close and ground relay coil causing relay contacts to close, thus applying battery voltage to cooling fan. On vehicles with
two speed cooling fans, low speed cooling fan relay coil is grounded through low speed contacts of A/C high pressure switch (with A/C on) or through
ground provided by ECM. On vehicles with Heavy Duty Two Speed cooling fan less A/C, ground is only provided by ECM with vehicle speed below 35
mph. With low speed cooling fan relay coil grounded, relay contacts close, applying battery voltage through cooling fan resistor to heavy duty fan or
directly to two speed fan. The resistor which is external with heavy duty cooling fan; internal with two speed fan, drops part of voltage so fan runs at low
speed. During high speed operation, high speed cooling fan relay coil is grounded through high speed contacts of A/C high pressure switch (with A/C
on) or cooling fan switch. With high speed cooling fan relay coil grounded, relay contacts close. Battery voltage is applied directly to cooling fan
causing it to run at high speed.
V6-231 VIN 3 WITH SINGLE SPEED FAN
Cooling Fan Does Not Run
1.
Check crank/fan fuse.
2.
Check that cooling fan case ground is clean and tight.
3.
Turn ignition switch to RUN without starting engine.
4.
Disconnect cooling fan switch connector (single dark green/yellow wire) and connect a jumper wire from dark green/yellow wire to ground and
leave connected for duration of test.
5.
If fan runs in step 4, replace cooling fan switch.
6.
If cooling fan does not run in step 4, connect test lamp to ground and check for voltage at terminal A (red wire) of connector on cooling fan relay.
7.
If test lamp does not light, check, and if necessary, repair open in red wire between relay and fusible link C. Check, and if necessary, repair open in
fusible link C (at starter solenoid).
8.
If test lamp lights in step 6, check for voltage at terminal E (brown wire) of connector on relay.
9.
If test lamp does not light, repair open in brown wire between relay and fuse block.
10.
If test lamp lights in step 8, check for voltage at terminal B (dark green/yellow wire) of connector on relay.
11.
If test lamp lights, repair open in dark green/yellow wire between relay and cooling fan switch.
12.
If test lamp does not light in step 10, check for voltage at terminal D (black/red wire) of connector on relay.
13.
If test lamp does not light, replace cooling fan relay.
14.
If test lamp lights in step 12, check for voltage at cooling fan connector (single black/red wire).
15.
If test lamp does not light, repair open in black/red wire between relay and cooling fan.
16.
If test lamp lights, repair or replace cooling fan.
Cooling Fan Does Not Run For Delay Period After Engine Is Shut Off With Coolant Hot
1.
Check ECM/ERLS fuse.
2.
Connect test lamp to ground and check for voltage at terminal A (red wire) of connector C1 on cooling fan delay relay.
3.
If test lamp lights, check, and if necessary, repair open in red wire between coolant fan delay relay and fusible link C.
4.
If test lamp lights, check for voltage at terminal A (red wire) of connector C2 on cooling fan delay relay.
5.
If test lamp does not light, check, and if necessary, repair red wire between delay relay and fusible link F.
6.
If test lamp lights in step 4, check for voltage at terminal C (black/pink wire) of connector C1 on delay relay.
7.
If test lamp lights, repair open in black/pink wire between delay relay and splice S181 (engine harness, front of LH shock tower).
8.
If test lamp does not light, disconnect cooling fan switch connector (single dark green/yellow wire) and connect a jumper from dark green/yellow
wire to ground. Turn ignition switch to RUN then off.
9.
If fan operates, replace cooling fan switch.
10.
If fan does not operate in step 8, check for voltage at terminal B (dark green/yellow wire) of connector C1 on delay relay.
11.
If test lamp does not light, replace cooling fan delay relay.
12.
If test lamp lights, repair open in dark green/yellow wire between delay relay and splice S182 (engine harness, top RH end of engine).
V6-231 VIN 3 WITH 2 SPEED FAN
Coolant Fan Does Not Run At Any Speed
1.
Check crank/fan fuse.
2.
Connect test lamp to ground and check for voltage at terminal E (brown wire) of high speed cooling fan relay.
