Magnet Clutch Circuit

WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.

SYMPTOM:

Magnet clutch does not engage when A/C switch and fan control switch are ON .

CHECK POWER SUPPLY FOR COMPRESSOR
Disconnect compressor harness connector.

Do approx. 12 volts exist between compressor harness connector E36-2 terminal No. 1, (B) and body ground?

Fig 1: Checking Power Supply For Compressor
Courtesy of NISSAN MOTOR CO., U.S.A.

Yes or No
- Yes: GO TO 2.
- No: GO TO 3.
CHECK MAGNET CLUTCH COIL
Disconnect magnet clutch connector.

Do approx. 3.2Ω exist between A/C compressor harness connector E36-2 terminal No. 1, (B) and body ground?

Fig 2: Checking Magnet Clutch Coil
Courtesy of NISSAN MOTOR CO., U.S.A.

Yes or No
- Yes: INSPECTION END .
- No: Replace magnet clutch. Refer to , "OVERHAUL ".
CHECK CIRCUIT CONTINUITY BETWEEN A/C RELAY AND COMPRESSOR HARNESS
Disconnect A/C relay.

Check circuit continuity between A/C relay harness terminal No. 3 and compressor harness terminal No. 1.

Fig 3: Checking Circuit Continuity Between A/C Relay Harness Terminal No 3 And Compressor Harness Terminal No 1
Courtesy of NISSAN MOTOR CO., U.S.A.

If OK, check harness for short .

OK or NG
- OK: GO TO 4.
- NG: Repair harness or connector.
CHECK POWER SUPPLY FOR A/C RELAY
Disconnect A/C relay.

Do approx. 12 volts exist between A/C relay harness terminal Nos. 1, 5 and body ground?

Fig 4: Checking Power Supply For A/C Relay
Courtesy of NISSAN MOTOR CO., U.S.A.

Yes or No
- Yes: GO TO 5.
- No: Check power supply circuit and 10A (No. 15) fuse at fuse block.
CHECK A/C RELAY AFTER DISCONNECTING IT
Refer to , "A/C RELAY ".

OK or NG
- OK: Reconnect A/C relay. GO TO 6.
- NG: Replace A/C relay.
CHECK COIL SIDE CIRCUIT OF A/C RELAY
Reconnect A/C relay.

Do approx. 12 volts exist between ECM harness connector F22 terminal No. 23 (L) (QG18DE) or F54 terminal No. 26 (L) (QR25DE) and body ground?

Battery voltage should exist .

Yes or No
- Yes: GO TO 8.
- No: Disconnect A/C relay. Disconnect ECM harness connector. GO TO 7.
  
  Fig 5: Checking Coil Side Circuit Of A/C Relay
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK CIRCUIT CONTINUITY BETWEEN A/C RELAY AND ECM HARNESS
Check circuit continuity between A/C relay harness connector E50 terminal No. 2 (L) and ECM harness connector F22 terminal No. 23 (L) (QG18DE) or F54 terminal No. 26 (L) (QR25DE).

Continuity should exist .

If OK, check harness for short .

OK or NG
- OK: Check ECM. .
  
  Fig 6: Checking Circuit Continuity Between A/C Relay Harness Connector E50 Terminal No 2 (L) And ECM Harness Connector F22 Terminal No 23 (L) (QG18DE)
  Courtesy of NISSAN MOTOR CO., U.S.A.
- NG: Repair harness or connector.
CHECK VOLTAGE FOR ECM
Do approx. 12 volts exist between ECM harness connector F22 (QG18DE) or F54 (QR25DE) terminal No. 44 (L/R) and body ground?

Battery voltage should exist .

Yes or No
- Yes: GO TO 9.
- No: Check harness and connector. If OK, check ECM. .
  
  Fig 7: Checking ECM Voltage
  Courtesy of NISSAN MOTOR CO., U.S.A.
CHECK REFRIGERANT PRESSURE SENSOR
Refer to , "REFRIGERANT PRESSURE SENSOR ".

OK or NG
- OK: GO TO 10.
- NG: Replace refrigerant pressure sensor.
CHECK POWER SUPPLY FOR THERMO CONTROL AMP.
Do approx. 12 volts exist between thermo control amp. harness terminal No. 1 and body ground?

Fig 8: Checking Power Supply For Thermo Control Amp
Courtesy of NISSAN MOTOR CO., U.S.A.

Yes or No
- Yes: GO TO 11.
- No:
  - Check power supply circuit and 10A (No. 15) fuse at fuse block .
    - If OK, check for open circuit in wiring harness.
      Repair or replace as necessary.
    - If NG, replace fuse and check wiring harness for short circuit.
      Repair or replace as necessary.
CHECK POWER SUPPLY FOR THERMO CONTROL AMP.
Do approx. 12 volts exist between thermo control amp. harness terminal No. 2 and body ground?

Fig 9: Checking Power Supply For Thermo Control Amp
Courtesy of NISSAN MOTOR CO., U.S.A.

Yes or No
- Yes: GO TO 12.
- No: Repair or replace thermo control amp.
CHECK THERMO CONTROL AMP. OPERATION
Disconnect thermo control amp. harness connector.

Check circuit continuity between thermo control amp. harness terminal No. 3 and body ground.

Fig 10: Checking Circuit Continuity Between Thermo Control Amp Harness Terminal No 3 And Body Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG
- OK: GO TO 13.
- NG: GO TO 14.
CHECK THERMO CONTROL AMP.
Refer to , "THERMO CONTROL AMP. ".

OK or NG
- OK: GO TO 14.
- NG: Replace thermo control amp.
CHECK CIRCUIT CONTINUITY BETWEEN THERMO CONTROL AMP. AND A/C CONTROL UNIT
Disconnect A/C control unit harness connector.

Check circuit continuity between thermo control amp. harness terminal No. 3 and A/C control unit harness terminal No. 7.

Fig 11: Checking Circuit Continuity Between Thermo Control Amp Harness Terminal No 3 And A/C Control Unit Harness Terminal No 7
Courtesy of NISSAN MOTOR CO., U.S.A.

If OK, check harness for short .

OK or NG
- OK: GO TO 15.
- NG: Repair harness or connector.
CHECK CIRCUIT CONTINUITY BETWEEN FAN CONTROL SWITCH AND A/C CONTROL UNIT
Disconnect A/C control unit and fan control switch.

Check circuit continuity between fan control switch harness terminal No. 6 and A/C control unit harness terminal No. 8.

Fig 12: Checking Circuit Continuity Between Fan Control Switch Harness Terminal No 6 And A/C Control Unit Harness Terminal No 8
Courtesy of NISSAN MOTOR CO., U.S.A.

If OK, check harness for short .

OK or NG
- OK: GO TO 16.
- NG: Repair harness or connector.
CHECK FAN CONTROL SWITCH GROUND
Disconnect fan control switch harness connector.

Does continuity exist between fan control switch harness terminal No. 5 and body ground?

Fig 13: Checking Fan Control Switch Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

Yes or No
- Yes: Replace A/C control unit.
- No: Repair harness or connector.