Air Conditioning Signal
NOTE:
This signal informs the PCM that there is a demand for cooling from the A/C system.
- Turn ignition off. Disconnect A/C pressure switch (all models) and A/C diode (Civic, Oasis, Odyssey & Prelude). See A/C SIGNAL COMPONENT LOCATIONS . Turn ignition on. Measure voltage between PCM connector terminals A27 and B20 (Accord, Oasis & Odyssey) or terminals A9 and C5 (Civic, CR-V & Prelude). See Figure . If 5 volts exists (battery voltage on CR-V & Prelude), go to next step. If specified voltage does not exist, go to step 4).
- Turn ignition off. Reconnect A/C pressure switch (all models) and A/C diode (Oasis, Odyssey & Prelude) connectors. Turn ignition on. Using a fused jumper wire, momentarily connect PCM connector terminals A17 and B20 (Accord, Oasis & Odyssey) or terminals A9 and A17 (Civic, CR-V, Oasis & Odyssey), several times. See Figure . If A/C compressor clutch makes a clicking sound, go to next step. If A/C compressor clutch does not make a clicking sound, go to step 5).
- Start engine. Turn A/C and blower motor switches on. If A/C operates, A/C signal is okay. If A/C does not operate, go to step6. 4)Turn ignition switch off. Disconnect the PCM connector A (Accord, Oasis & Odyssey), C (Civic, CR-V & Prelude). Check for continuity between ground and terminals A27 (Accord, Oasis & Odyssey) or C5 (Civic, CR-V & Prelude). If continuity does not exist then substitute a known-good PCM then recheck for voltage. Repeat step 1). If continuity exists, then repair short in wire between A27 or C5 and A/C pressure switch. If specified voltage now exists, replace original PCM. If specified voltage still does not exist, inspect A/C system. Refer to appropriate A/C - HEATER SYSTEM article in the AIR CONDITIONING & HEAT section.
- Using a fused jumper wire, momentarily connect under-hood fuse/relay box 16-pin connector terminal No. 11 (Accord) or under-hood fuse/relay box 9-pin connector terminal No. 5 (Civic & CR-V) or A/C clutch relay connector terminal No. 4 (Oasis, Odyssey & Prelude)to ground several times. to ground several times. See Fig 1 & 6. See A/C SIGNAL COMPONENT LOCATIONS . If A/C compressor clutch makes a clicking sound, repair open in wire between A/C clutch relay and PCM connector terminal A17 (all models). See WIRING DIAGRAMS article. If A/C compressor clutch does not make a clicking sound, inspect A/C system. Refer to appropriate A/C - HEATER SYSTEM article in the AIR CONDITIONING & HEAT section.
- Turn ignition off. Disconnect PCM connectors "A" and "B" (Accord, Oasis & Odyssey) or "A" and "C" (Civic, CR-V & Prelude). Measure voltage between terminals A27 and B20 (Accord, Oasis & Odyssey) or A9 and C5 (Civic, CR-V & Prelude). If there is less that 1 volt measured, then substitute a known-good PCM then recheck for voltage. If specified voltage now exists, replace original PCM. If specified voltage still does not exist, inspect A/C system. Refer to appropriate A/C - HEATER SYSTEM article in the AIR CONDITIONING & HEAT section.
A/C SIGNAL COMPONENT LOCATIONS
| A/C Component | Location | |
|---|---|---|
| Accord | ||
| Clutch Relay | Under-hood fuse/relay box. | |
| Pressure Switch | On Receiver/Dryer at right front corner of condenser. | |
| Civic | ||
| Clutch Relay | Under-hood fuse/relay box. | |
| Diode | Under-hood fuse/relay box. | |
| Pressure Switch | On Receiver/Dryer at left front corner of engine compartment, next to power steering fluid reservoir. | |
| CR-V | ||
| Clutch Relay | Under-hood fuse/relay box. | |
| Pressure Switch | On Receiver/Dryer at left front corner of engine compartment, next to power steering fluid reservoir. | |
| Oasis & Odyssey | ||
| Clutch Relay | Under-hood fuse/relay box. | |
| Pressure Switch | On Receiver/Dryer at right front corner of condenser. | |
| Prelude | ||
| Clutch Relay | Left front corner of engine compartment. | |
| Diode | Left front of passenger's footwell under middle of instrument panel. | |
| Pressure Switch | On Receiver/Dryer at right front corner of condenser. | |