LEMON Manuals: Even more car manuals for everyone
Home >> Isuzu >> 1998 >> Trooper LS >> Repair and Diagnosis >> External Pages >> Different car >> Section 7 (A/C-Heater System) >> Testing >> Compressor Clutch Does Not Engage

Compressor Clutch Does Not Engage

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1999 Isuzu Rodeo, 1999 Isuzu Amigo, 1999 Honda Passport, 1998 Isuzu Rodeo, and 1998 Isuzu Amigo. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check 10-amp and 20-amp blower and A/C fuses. If blown, replace fuses. If not, check heater, compressor and thermostat relays. See RELAYS  . If relays are okay, go to next step.
  2. Check continuity of triple-pressure or pressure switch harness connector. See PRESSURE SWITCH under SWITCHES  . If switch tests out okay, go to next step. If switch does not test out okay, check refrigerant level. If refrigerant level is correct, replace defective pressure switch.
  3. Check A/C switch and blower switch. See SWITCHES  . If switches are okay, start engine. Turn A/C on. Measure voltage at Brown/Yellow wire terminal of compressor clutch harness connector. If battery voltage does not exist, go to next step. If battery voltage does exist, go to step  5 .
  4. Check for battery voltage at Brown wire of dual-pressure switch for manual transmission models or Green/White wire of triple-pressure switch for automatic transmission models. If there is no battery voltage, repair open wire between A/C fuse (10-amp) and dual/triple pressure switch. If battery voltage exists, go to next step.
  5. Check for continuity between compressor side of connector terminal and clutch side of connector terminal. If there is continuity, magnetic clutch is defective. Replace clutch. If there is no continuity, compressor is defective. Replace compressor. Check for battery voltage at chassis side of A/C switch connector Brown wire terminal. If there is battery voltage, go to next step. If there is no battery voltage, repair open circuit between 10-amp fuse and A/C switch.
  6. Check for battery voltage at chassis side of dual-pressure switch connector Brown wire terminal or Pink/White wire of triple-pressure switch. If there is battery voltage, go to next step. If there is no battery voltage, repair open circuit between A/C switch and pressure switch.
  7. Disconnect thermoswitch relay. Measure voltage at Brown wire terminal of thermoswitch relay harness connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair open Brown wire of dual-pressure switch or Pink/White wire of triple-pressure switch.
  8. Measure voltage between Green/White wire and Green/Red wire terminals of thermoswitch relay harness connector. If battery voltage does not exist, go to step  15 . If battery voltage exists, reconnect thermoswitch relay, and go to next step.
  9. Disconnect A/C compressor relay. Measure voltage at Brown/Yellow wire terminal of A/C compressor relay harness connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair open Brown/Yellow wire between A/C fuse (10-amp) and A/C compressor relay.
  10. Check continuity between Brown wire terminal of A/C compressor relay and compressor clutch. If continuity exists, go to next step. If continuity does not exist, repair open Brown wire.
  11. Measure voltage between the opposing Brown wire and Green/Red wire terminals of A/C compressor relay. If battery voltage exists, go to next step. If battery voltage does not exist, check voltage at Green/Red wire terminal of Powertrain Control Module (PCM) harness connector. If battery voltage exists, replace defective PCM. If battery voltage does not exist, repair open circuit between Green/Red wire of A/C compressor relay and PCM.
  12. Measure voltage at Brown wire terminal (opposing Green/Red wire terminal) of A/C compressor relay. If battery voltage exists, go to next step. If battery voltage does not exist, repair open wire between 10-amp fuse and A/C compressor relay.
  13. Check continuity between Green/Black wire of A/C thermoswitch relay and PCM harness connector. If continuity exists, replace defective PCM. If there is no continuity, repair open circuit.
  14. Measure voltage at Green/White wire terminal of thermoswitch relay harness connector. If there is battery voltage, go to next step. If there is no battery voltage, repair open circuit between thermoswitch and dual pressure switch.
  15. Reconnect thermoswitch relay. Measure voltage at Light Green/Black wire terminal of electronic thermostat harness connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair open Light Green/Black wire between electronic thermostat and A/C switch.
  16. Check continuity between White wire terminals of electronic thermostat harness connector and blower switch. If continuity exists, replace defective electronic thermostat. If continuity does not exist, repair open White wire or poor ground.
scientia non olet · About LEMON Manuals