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Air Conditioning Signal: 2.3CL

  1. Turn ignition off. Disconnect A/C pressure switch and A/C diode connectors. A/C pressure switch 2-pin connector is located at lower right front side of engine compartment, near receiver dryer. A/C diode 2-pin connector is taped to harness under left side of dash, behind kick panel. Turn ignition on. Backprobing, measure voltage between PCM 32-pin connector terminal No. 27 (Red/White wire) and 25-pin connector terminal No. 20 (Brown/Black wire). See Figure. If battery voltage is not present, go to next step. If battery voltage is present, go to step 3).
  2. Turn ignition off. Disconnect PCM 32-pin connector. Check continuity between ground and PCM 32-pin harness connector terminal No. 27 (Red/White wire). See Figure. If continuity exists, repair short in Red/White wire between PCM 32-pin connector terminal No. 27 and A/C pressure switch. If continuity does not exist, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM. Ensure A/C is operating properly. See A/C-HEATER SYSTEM article in AIR CONDITIONING & HEAT section.
  3. Turn ignition off. Reconnect A/C pressure switch and A/C diode connectors. Turn ignition on. Using a fused jumper wire, momentarily connect PCM 32-pin connector terminals No. 17 (Red/Blue wire) and 25-pin connector terminal No. 20 (Brown/Black wire) several times. See Figure. If A/C clutch does not click, go to next step. If A/C clutch clicks, go to step 5).
  4. Locate A/C clutch relay at left side of engine compartment, above cooling fan. Using a fused jumper wire, backprobing, momentarily connect A/C clutch relay connector terminal No. 4 (Red/Blue wire) to ground several times. If A/C clutch clicks, repair open in Red/Blue wire between PCM 32-pin connector terminal No. 17 and A/C clutch relay 4-pin connector. If A/C clutch does not click, problem is with A/C system. See A/C-HEATER SYSTEM article in AIR CONDITIONING & HEAT section.
  5. Start engine. Turn blower motor switch on. Turn A/C switch on. If A/C operates, A/C signal is okay at this time. If A/C does not operate, measure voltage between PCM 32-pin connector terminal No. 27 (Red/White wire) and PCM 25-pin connector terminal No. 20 (Brown/Black wire). See Figure. If voltage is not less than one volt, repair open in Red/White wire between PCM 32-pin connector terminal No. 27 and A/C pressure switch. If voltage is less than one volt, substitute a known good PCM, then recheck. If symptom or indication goes away, replace original PCM. Ensure A/C is operating properly. See A/C-HEATER SYSTEM article in AIR CONDITIONING & HEAT section.
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