1999 Acura 2.3CL AutomaticFACTORY OEM SERVICE PROCEDURE

Air Conditioning Signal: Integra

  1. Turn ignition off. Disconnect A/C pressure switch and A/C diode connectors. A/C pressure switch Gray, 2-pin connector is located at left front of engine compartment, between radiator and compressor. A/C diode White, 3-pin connector is located under right side of dash, behind kick panel. Turn ignition on. Backprobing, measure voltage between PCM 32-pin connector terminal No. 9 (Brown/Black wire) and 31-pin connector terminal No. 5 (Blue/Red wire). See Figure. If voltage is not about 5 volts, go to next step. If voltage is about 5 volts, go to step  3.
  2. Turn ignition off. Disconnect PCM 31-pin connector. Check continuity between ground and PCM 31-pin harness connector terminal No. 5 (Blue/Red wire). See Figure. If continuity exists, repair short in Blue/Red wire between PCM 31-pin connector terminal No. 5 and A/C pressure switch or A/C diode. 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 MANUAL A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
  3. Turn ignition off. Reconnect A/C pressure switch and A/C diode connectors. Turn ignition on. Using a fused jumper wire, backprobing, momentarily connect PCM 32-pin connector terminals No. 9 (Brown/Black wire) and No. 17 (Black/Red 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 Brown, 4-pin connector behind left side of front bumper. Using a fused jumper wire, momentarily backprobe A/C clutch relay connector terminal No. 4 (Black/Red wire) to ground several times. If A/C clutch clicks, repair open in Black/Red 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 MANUAL A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
  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, backprobing, measure voltage between PCM 32-pin connector terminal No. 9 (Brown/Black wire) and PCM 31-pin connector terminal No. 5 (Blue/Red wire). See Figure. If voltage is one volt or more, repair open in Blue/Red wire between PCM 31-pin connector terminal No. 5 and A/C pressure switch or A/C diode connectors. 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 MANUAL A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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