Engine Cooling Fan — Cadillac Seville IV (1992-1997)

ELECTRIC COOLING FAN

Note. Fleetwood with heavy-duty cooling package uses conventional fan and thermostatically controlled fan clutch assembly.

DESCRIPTION & OPERATION

Note. For component location and terminal identification, see WIRING DIAGRAMS at the end of this article.

Fleetwood (Primary Fan)

When coolant reaches a predetermined temperature, Electronic Control Module (ECM) de-energizes cooling fan control relay. This will energize primary cooling fan relay to complete circuit from underhood Fuse No. 8 (50-amp) to primary cooling fan.

Fleetwood (Secondary Fan)

Secondary cooling fan operates when terminal A2 of secondary cooling fan relay is grounded. This occurs when coolant temperature reaches 232°F (111°C) or A/C head pressure reaches 200-300 psi (14.1-21.1 kg/cm 2 ). Current is supplied through underhood Fuse No. 7 (50-amp) to secondary cooling fan.

Cooling fans will also operate in some fail-safe modes and when ECM trouble Code 14 or 15 is present.

DeVille/Sixty-Special (Low Speed)

When coolant temperature reaches 208°F (98°C), Powertrain Control Module (PCM) grounds low speed relay coils (PCM connector C2, terminal A11). This energizes low speed relay, completing circuit to left and right cooling fans. Under this condition, full battery voltage is applied to right cooling fan which operates at high speed. Left cooling fan operates at low speed because circuit runs through cooling fan resistors.

DeVille/Sixty-Special (High Speed)

Full battery voltage continues to be applied to right cooling fan through low speed relay. See DEVILLE/SIXTY-SPECIAL (LOW SPEED) . When coolant temperature reaches 226°F (106°C) or A/C high side temperature reaches 212°F (100°C), PCM grounds high speed relay coils (PCM connector C2, terminal B8). This energizes high speed relay. Full battery voltage is applied to left cooling fan which now runs at high speed.

Eldorado & Seville (Low Speed)

Powertrain Control Module (PCM) grounds coils of cooling fan relay No. 1 (at PCM terminal 2A11) when coolant temperature exceeds 223°F (106°C) or A/C high side temperature exceeds 140°F (60°C). Cooling fans may also activate when all these conditions exist

Vehicle speed is less than 20 MPH
A/C compressor clutch engagement is possible
Outside air temperature is greater than 45°F (7°C)

When cooling fan relay No. 1 is energized, circuit is completed through left side fan, cooling fan relay No. 2 (terminals No. 1 and 3), right side fan and ground. Both motors operate at low speed due to series circuit resistance of both motors.

Eldorado & Seville (High Speed)

Powertrain Control Module (PCM) grounds coils of cooling fan relays No. 1, 2 and 3 (at PCM terminals 2A11 and 2B8) under any of the following conditions

Coolant temperature exceeds 226°F (108°C)
Coolant temperature sensor circuit failure exist
A/C high side temperature exceed 158°F (70°C)
A/C high side temperature sensor failure exists

When cooling fan relays No. 1 and 2 are energized, cooling fan relay No. 3 is energized. When all 3 relays are energized, full battery voltage is applied to both cooling fans, which operate at high speed (parallel circuit).

TROUBLE SHOOTING

Note. When cooling fan relays No. 1 and 2 are energized, cooling fan relay No. 3 is energized. When all 3 relays are energized, full battery voltage is applied to both cooling fans, which operate at high speed (parallel circuit).

Preliminary Check

Enter self-diagnostics and check for codes. If no codes are present, go to next step. If codes are present, repair system as necessary.
If fans do not operate, check wiring to inoperative fan. If wiring is okay, apply current directly to fan. If fan does not operate, replace fan. If fan operates, perform appropriate test under TESTING.

DEVILLE/SIXTY-SPECIAL

Note. On DeVille/Sixty-Special, COOLING FAN SYSTEM OVERRIDE TEST can be used to localize problem by overriding normal operation of fan control system and manually operating cooling fans.

Cooling Fan System Override Test

Enter self-diagnostics and check for codes. If codes are present, repair system before continuing.
If no codes are present, select cooling fan mode of PCM output overrides (E.5.8). In this mode, "00" will appear on diagnostic display. No voltage is applied to cooling fan relays in this mode.
Push COOLER button on A/C control panel. Left digit of display will change to "1". Display now reads "10" and low speed cooling fan relay is energized. This supplies voltage to right cooling fan and low speed circuit of left cooling fan.
Push WARMER button on A/C control panel. Right digit of display will change to "1". Display now reads "11" and low and high speed cooling fan relays are energized. This supplies voltage to right cooling fan and high speed circuit of left cooling fan. Proceed to appropriate test.

Neither Cooling Fan Operates

While in cooling fan system override test, turn on both cooling fans. See «COOLING FAN SYSTEM OVERRIDE TEST»(/cadillac/seville/iv-1992-1997/remont/cooling-fan/#engine-cooling-fan__cooling-fan-system-override-test) .
If cooling fans do not operate as specified in test, go to step 5). If cooling fans operate as specified, start engine. Turn on A/C. Run engine at idle for a few minutes.
Enter self-diagnostics. Read PCM DATA - COOLANT TEMPERATURE SENSOR and BCM DATA - REFRIGERANT HIGH SIDE TEMPERATURE SENSOR. If both temperatures indicated on display are above ambient temperature and are increasing, replace PCM.
If one or both temperatures indicated on display remain at or below ambient temperature, check wiring to sensor. If wiring is okay, replace sensor.
Disconnect high speed cooling fan relay. Measure voltage between high speed cooling fan relay connector terminal No. 1 (Red wire) and ground. If battery voltage is present, go to next step. If voltage is not present, replace fuse No. 4 in left underhood fuse block or repair Red wire.
Turn ignition switch to RUN position. Measure voltage between high speed cooling fan relay connector terminal No. 2 (Brown wire) and ground.
If battery voltage is present, repair open in Black wires between cooling fans and ground. If voltage is not present, replace fuse No. 6 in instrument panel fuse block or repair Brown wire. NOTE: When activated, right cooling fan operates at high speed only.

Left Cooling Fan Does Not Operate At Low Speed

While in cooling fan system override test, turn on cooling fans at low speed. See «COOLING FAN SYSTEM OVERRIDE TEST»(/cadillac/seville/iv-1992-1997/remont/cooling-fan/#engine-cooling-fan__cooling-fan-system-override-test) .
If cooling fans do not operate, go to step 5). If cooling fans operate, start engine. Turn on A/C. Run engine at idle for a few minutes.
Enter self-diagnostics. Read PCM DATA - COOLANT TEMPERATURE SENSOR and BCM DATA - REFRIGERANT HIGH SIDE TEMPERATURE SENSOR. If both temperatures indicated on display are greater than ambient temperature and are increasing, replace PCM.
If one or both temperatures indicated on display remain at or less than ambient temperature, check wiring to sensor. If wiring is okay, replace sensor.
Turn ignition switch to RUN position. With PCM harness connected, connect fused jumper wire between ground and PCM connector C2, terminal A11 (Gray/Black wire). If cooling fans operate, replace PCM. If cooling fans do not operate, leave jumper wire connected and go to next step.
Measure voltage between ground and low speed cooling fan relay connector terminal No. 1 (Red wire). If battery voltage is present, go to next step. If voltage is not present, check Red wire.
Measure voltage between low speed cooling fan relay connector terminals No. 1 (Red wire) and 5 (Gray/Black wire). If battery voltage is present, go to next step. If voltage is not present, check Gray/Black wire.
Measure voltage between ground and low speed cooling fan relay connector terminal No. 2 (Brown wire). If battery voltage is present, go to next step. If voltage is not present, check Brown wire.
Connect fused jumper wire between low speed cooling fan relay connector terminals No. 2 (Brown wire) and 4 (Black/Red wire). If cooling fans operate, replace low speed cooling fan relay. If cooling fans do not operate, check Black/Red wire. If wire is okay, check cooling fan resistors and wiring harness.

Both Cooling Fans Do Not Operate In High Speed

While in cooling fan system override test, turn on cooling fans at high speed. See «COOLING FAN SYSTEM OVERRIDE TEST»(/cadillac/seville/iv-1992-1997/remont/cooling-fan/#engine-cooling-fan__cooling-fan-system-override-test) .
If cooling fans do not operate, go to step 5). If cooling fans operate, start engine. Turn on A/C. Run engine at idle for a few minutes.
Enter self-diagnostics. Read PCM DATA - COOLANT TEMPERATURE SENSOR and BCM DATA - REFRIGERANT HIGH SIDE TEMPERATURE SENSOR. If both temperatures indicated on display are greater than ambient temperature and are increasing, replace PCM.
If one or both temperatures indicated on display remain at or less than ambient temperature, check wiring to sensor. If wiring is okay, replace sensor.
Turn ignition switch to RUN position. With PCM harness connected, connect fused jumper wire between ground and PCM connector C2, terminal B8 (Dark Green/White wire). If cooling fans operate, replace PCM. If cooling fans do not operate, leave jumper wire connected and go to next step.
Measure voltage between ground and high speed cooling fan relay connector terminal No. 1 (Red wire). If battery voltage is present, go to next step. If voltage is not present, check Red wire.
Measure voltage between high speed cooling fan relay connector terminals No. 1 (Red wire) and 5 (Dark Green/White wire). If battery voltage is present, go to next step. If voltage is not present, check Dark Green/White wire.
Measure voltage between ground and high speed cooling fan relay connector terminal No. 2 (Brown wire). If battery voltage is present, go to next step. If voltage is not present, check Brown wire.
Connect fused jumper wire between high speed cooling fan relay connector terminals No. 2 (Brown wire) and 4 (Black/Pink wire). If cooling fans operate, replace high speed cooling fan relay. If cooling fans do not operate, check Black/Pink wire.

No Low Speed (Both Fans), No High Speed (Both Fans)

Check fusible link No. 6 (if horn operates, fusible link is okay). If fusible link is open, repair short in wiring. If fusible link is okay, check for battery voltage at Red wire terminals of cooling fan relays No. 1 and No. 3.
If voltage is not present at one or both terminals, repair open in Red wire circuit. If voltage is present at both terminals, remove cooling fan relay No. 1 from underhood relay center. Turn ignition switch to RUN position.
Measure voltage between ground and Pink/White wire terminal of cooling fan relay No. 1. If voltage is not present, check coolant fan fuse D3 in underhood relay center and Pink/White wire circuit. If battery voltage is present, check wiring between relays and cooling fans and repair as necessary.
If battery voltage is present, check for open in Gray/Black wire circuit between PCM and cooling fan relay No. 1 and Dark Green/White wire circuit between PCM and cooling fan relay No. 2. If both circuits are okay, replace PCM.

No Low Speed (Both Fans), No High Speed (Pusher Fan)

Remove cooling fan relay No. 1 from underhood relay center. Turn ignition switch to RUN position. Measure voltage between ground and Red and Pink/White wire terminals of cooling fan relay No. 1.
If battery voltage is present, go to next step. If voltage is not present, check all the following: coolant fan fuse D3 in underhood relay center, Pink/White wire circuit, fusible link No. 6 and Red wire circuit.
Connect a jumper wire from PCM harness connector terminal A11 (Gray/Black wire) to known good ground (no voltage should be present in Gray/Black wire). Turn ignition on. Connect test light between Pink/White and Gray/Black wire terminals of cooling fan relay No. 1.
If test light illuminates, go to next step. If test light does not illuminate, check for open or short to battery (B+) in Gray/Black wire circuit between cooling fan relay No. 1 and PCM. If circuit is okay, disconnect jumper wire and replace PCM with known good PCM. If fans now operate, replace PCM. If fans do not operate, go to next step.
Connect a fused jumper wire between Red and Black/Gray wire terminals of cooling fan relay No. 1. If cooling fans do not run at low speed, leave jumper wire connected and go to next step. If cooling fans run at low speed, check for poor connections at relay. If relay connections are okay, replace cooling fan relay No. 1.
Remove cooling fan relay No. 2. Connect jumper wire between ground and terminal No. 1 harness connector (Black/Pink wire) of cooling fan relay No. 2. If pusher fan runs at high speed, check/replace cooling fan relay No. 2.
If pusher fan does not run at high speed, check for open in Black/Pink wire between cooling fan relay No. 2 and pusher fan, and Black/Red wire between cooling fan relay No. 1 and pusher fan. If wires are okay, replace pusher fan.

Low Speed OK (Both Fans), No High Speed (Pusher Fan)

Remove cooling fan relay No. 2 from underhood relay center. Turn ignition switch to RUN position. Measure voltage between Pink/White and Black wire terminals of cooling fan relay No. 2.
If voltage is not present, repair open in Black wire between cooling fan relay No. 2 and ground. If battery voltage is present, check for poor connection at cooling fan relay No. 2. If connection is okay, replace cooling fan relay No. 2.

Low Speed OK (Both Fans), No High Speed (Puller Fans)

Remove cooling fan relay No. 3 from underhood relay center. Turn ignition switch to RUN position. Measure voltage between ground and Red and Pink/White wire terminals of cooling fan relay No. 3.
If battery voltage is present, go to next step. If voltage is not present, check coolant fan fuse D3 in underhood relay center, Pink/White wire circuit, fusible link No. 6 and Red wire circuit.
Use an ohmmeter to check continuity in Dark Green/White wire circuit. If okay, connect a fused jumper wire between Red and Black/Pink wire harness terminals of cooling fan relay No. 3.
If puller fan does not run at high speed, repair open in Black/Pink wire between cooling fan relay No. 3 and puller fan. If puller fan runs at high speed, check for poor connection at cooling fan relay No. 3. If connection is okay, check/replace cooling fan relay No. 3.

Low Speed OK (Both Fans), No High Speed (Both Fans)

Remove cooling fan relays No. 2 and 3 from underhood relay center. Turn ignition switch to RUN position. Measure voltage between ground and Pink/White wire terminal of cooling fan relay No. 2, and Red and Pink/White wire terminals of cooling fan relay No. 3.
If battery voltage is present on all terminals, go to next step. If voltage is not present on one or more terminals, check for open wiring, fusible link No. 6 or coolant fan fuse D3.
Check for open in Dark Green/White wire circuit. If circuit is okay, replace PCM with known good PCM. If cooling fans operate at high speed, replace PCM.

Continuous Low (Both Fans) With Ignition On or Off

Check for short to voltage in Black/Pink wire between cooling fan relay No. 2 and fan motors.

Continuous Low (Both Fans) With Ignition In RUN Position

Check for short to ground in Gray/Black wire circuit between cooling fan relay No. 1 and PCM. If circuit is okay, replace PCM.

No Low Speed (Both Fans), High OK (Both Fans)

Check for open in Black/Pink wire circuit. Also check for continuity between terminals No. 1 and 3 of cooling fan relay No. 2. Replace relay if necessary.

Continuous High (Puller Fan) With Ignition Switch On or Off

Check for short to battery (B+) in Black/Pink wire circuit. If circuit is okay, replace cooling fan relay No. 3.

Continuous High (Puller Fan) With Ignition Switch In RUN Position

Check for short to ground in Dark Green/White wire circuit. If circuit is okay, replace PCM.

No Low Speed (Both Fans), No High Speed (Puller Fan)

Check for open condition in Black/Pink wire between puller fan and wiring splice (splice between puller fan and cooling fan relay No. 3). Check for open in Black wire between puller fan and wiring splice (splice between puller fan and ground. Check for open between puller fan and puller fan connector.

Check for short to ground in Black/Pink wire between pusher fan and cooling fan relay No. 2. If circuit is okay, replace cooling fan relay No. 2.