Nissan 240sx S13 Engine Cooling Fans: condenser, radiator fan motor and more

Nissan 240sx S13

TROUBLE SHOOTING

NOTE: ECM refers to ECCS control unit. ECM controls cooling fan operation based on inputs from coolant temperature sensor and AC switch.

CONDENSER FAN CONTROL TEST

Condenser (Cooling) Fan Control Test
1. Start engine and warm to operating temperature. Set temperature lever to full cold. Turn AC switch on. Turn fan switch on. Run engine at idle with AC on for several minutes. Ensure condenser fan operates. If fan does not operate, go to next step. If fan operates, system is functioning properly.
2. Turn AC and fan switches off. Turn ignition off. Disconnect condenser fan relay. See Fig. 1. Turn ignition on. Measure voltage between ground and condenser fan relay harness connector terminals No. 2 (Blue/Orange wire) and No. 3 (Black/White wire). Battery voltage should be present. If battery voltage is present, go to step 4). If battery voltage is not present, go to next step.
3. Check Gray and Green fusible links located in fuse and relay box next to battery. Replace fusible links as necessary. Check 10-amp fuse located in fuse box under left side of instrument panel. Replace fuse as necessary. If fusible links and 10-amp fuse are okay, repair open in harness or connectors.
4. Turn ignition off. Disconnect condenser fan motor harness connector. Check continuity between condenser fan motor harness connector terminal "a" (Brown/White wire) and condenser fan relay harness connector terminal No. 5 (Brown/White wire). See Fig. 2 . Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Brown/White wire.
5. Check continuity between ground and condenser fan motor harness connector terminal "b" (Black wire). See Fig. 2 . Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire.
6. Disconnect ECM harness connector. ECM is located behind passenger side kick panel. Check continuity between ECM harness connector terminal No. 9 (Orange/Blue wire) and condenser fan relay harness connector terminal No. 1 (Orange/Blue wire). See Fig. 2 and Fig. 5 . Continuity should exist. If continuity exists, go to next step. If continuity does not exist, repair open in Orange/Blue wire.
7. Check condenser fan relay. Replace relay as necessary. If relay is okay, check condenser fan motor. Replace fan motor as necessary. If fan motor is okay, inspect ECM and ECM harness connector terminals for damage, corrosion and improper connection. Repair as necessary.

Condenser Fan Motor Test
Apply battery voltage and ground across fan motor connector terminals. Fan motor should operate. If fan motor does not operate, replace fan motor.

Fig. 1: Locating Condenser Fan Relay

Fig. 2: Testing Condenser Fan Circuit

COMPONENT TESTING

Radiator Fan Motor
Disconnect fan motor harness connector(s). Apply battery voltage and ground across fan motor terminals and observe motor operation. See Fig. 3 . See RADIATOR FAN MOTOR OPERATION table. If motor does not operate as indicated, replace motor.

RADIATOR FAN MOTOR OPERATION

• Motor Number 1
  • Motor Speed: Low
  • Battery Positive (+): "b"
  • Battery Negative (-): "c"
• Motor Number 1
  • Motor Speed: High
  • Battery Positive (+): "a" and "b"
  • Battery Negative (-): "c" and "d"
• Motor Number 2
  • Motor Speed: Low
  • Battery Positive (+): "b"
  • Battery Negative (-): "c"
• Motor Number 2
  • Motor Speed: High
  • Battery Positive (+): "a" and "b"
  • Battery Negative (-): "c" and "d"

Fig. 3: Testing Radiator Fan Motors

Relays
1. Identify relay type by color. See Fig. 4 . Check continuity between relay terminals No. 3 and 5. On Brown relay, also check continuity between terminals No. 6 and 7. If continuity is present, replace relay. If continuity is not present, go to next step.
2. Apply battery voltage across terminals No. 1 and 2. Check continuity between terminals No. 3 and 5. On Brown relay, also check continuity between terminals No. 6 and 7. If continuity is not present, replace relay. If continuity is present, relay is okay.

Fig. 4: Cooling Fan Relay Connector Terminals and Internal Circuits ID



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Nissan 240sx S13

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