C: A/C DOES NOT OPERATE/DOES NOT OPERATE PROPERLY

PINPOINT TEST C: A/C DOES NOT OPERATE/DOES NOT OPERATE PROPERLY

C1 CHECK A/C CLUTCH OPERATION

NOTE: Outside temperature must be above l0°C (50° F) for A/C compressor operation.

- Start engine.
- Set A/C control at MAX A/C.
- Check battery voltage. If not 12.5 volts refer to Starting and Charging/Charging System/Testing and Inspection for charging system diagnosis. Testing and Inspection
- Rotate blower speed switch to HI.

- Does A/C clutch engage?

- Yes
A/C clutch circuit functioning properly.

- No
Go to C2.

C2 CHECK A/C CYCLING SWITCH

- Disconnect electrical connector from A/C cycling switch.
- Jumper harness connector pins.
- Engine must be running, A/C on, and blower switch on HI.

- Does A/C clutch engage?

- Yes
Go to C3.

- No
Go to C4.

C3 CHECK REFRIGERANT SYSTEM PRESSURE

- Turn engine off if engine is operating.
- Connect gauge set to service ports.
- Reading must be above 345 kPa (50 psi).

- Is pressure above 345 kPa (50 psi)?

- Yes
Replace A/C cycling switch. Go to C1

- No
Check system for refrigerant system leaks or low charge. Service and charge system as required. Go to C1.

C4 CHECK B+ TO A/C CYCLING SWITCH

- Engine off and ignition switch in RUN position.
- Set A/C control at MAX A/C.
- Check for battery voltage at A/C cycling switch harness connector, Circuit 348 (P) to ground.

- Is there B+?

- Yes
Go to C5.

- No
Go to C15

C5 CHECK B+ TO A/C PRESSURE CUT-OFF SWITCH

- Engine off and ignition switch in RUN position.
- Set A/C control at MAX A/C.
- Check for B+ at A/C pressure cut-off switch harness connector, Circuit 883 (PK/LB) to ground.

- Is there B+?

- Yes
Go to C6.

- No
Service circuit 883 (PK/LB) for open. Restore vehicle. Retest system.

C6 CHECK A/C PRESSURE CUT-OFF SWITCH CONTACT CONTINUITY

- Engine off and ignition switch in RUN position.
- Set A/C control at MAX A/C.
- Check continuity between A/C pressure cut-off switch contacts.

- Does continuity exist?

- Yes
Go to C7.

- No
Replace A/C pressure cut-off switch. Restore vehicle. Retest system.

C7 CHECK FOR B+ TO A/C COMPRESSOR CLUTCH CONTROL RELAY AT RELAY CENTER

- Turn engine OFF, leave ignition switch in RUN position.
- Set A/C control at MAX A/C.
- Check for B+ at Pin 30, Circuit 198 (DG/O) of A/C compressor clutch control relay harness connector to ground.

- Is there B+?

- Yes
Go to C8.

- No
Service open circuit 198 (DG/O). Retest system.

C8 CHECK PCM INPUT VOLTAGE FROM A/C PRESSURE CUT-OFF SWITCH

- Engine off and ignition switch in RUN position.
- A/C control at MAX A/C.
- Using a digital voltlohmmeter check for voltage at PCM Circuit 198 (DG/O).

- Is voltage present?

- Yes
Go to C9.

- No
Service open circuit 198 (DG/O). Retest system.

C9 CHECK PCM PIN 85 CIRCUIT 73 (O/LB) OUTPUT TO A/C COMPRESSOR CLUTCH CONTROL RELAY

- Disconnect Pin 85, Circuit 73 (O/LB) at A/C compressor clutch control relay.

- Does A/C clutch engage?

- Yes
Refer to Powertrain Management/Computers and Control Systems/Testing and Inspection for WOT cutout and ECT testing. Service as required. Retest system. Testing and Inspection

- No
Go to C10.

C10 CHECK A/C COMPRESSOR CLUTCH CONTROL RELAY OUTPUT TO A/C CLUTCH

- Engine off and ignition switch in RUN position.
- A/C control at MAX A/C.
- Using voltmeter, check A/C compressor clutch control relay Pin 87A, Circuit 347 (BK/Y) for B+.

- Is there B+?

- Yes
Go to C11.

- No
Replace A/C compressor clutch control relay.

C11 CHECK VOLTAGE SUPPLY TO A/C CLUTCH

- Engine off and ignition switch in RUN position.
- A/C control at MAX A/C.
- Disconnect A/C clutch electrical connector.
- Using a voltmeter, check Circuit 347 (BK/Y) at A/C clutch connector for voltage.

- Is there voltage?

- Yes
Go to C12.

- No
Service circuit 347 (BK/Y) for open circuit. Restore vehicle. Retest system.

C12 CHECK A/C CLUTCH GROUND CIRCUIT

- Using an ohmmeter connected to ground, connect second lead to Circuit 57 (BK) at A/C clutch connector.
- Measure resistance.

- Is resistance one ohm or less?

- Yes
Go to C13.

- No
Service circuit 57 (BK). Retest system.

C13 CHECK A/C CLUTCH FIELD COIL RESISTANCE

- Engine off and ignition switch in RUN position.
- A/C control at MAX A/C.
- Using an ohmmeter, check the resistance between the two terminals of the A/C clutch field coil.

- Is the resistance 6 ohms or less?

- Yes
Replace A/C clutch field coil. Restore vehicle. Retest system.

- No
Go to C14

C14 CHECK A/C CLUTCH FIELD COIL CURRENT DRAW

- Using an ampmeter, check current draw of A/C clutch field coil.

- Is current draw between 2.5 4.5A?

- Yes
Service A/C clutch air gap. Restore vehicle. Retest system.

- No
Replace A/C clutch field coil. Restore vehicle. Retest system.

C15 CHECK B+ TO A/C DAMPER DOOR SWITCH

- Turn engine off and ignition switch in RUN position.
- Using a voltmeter, check for voltage at Pin 2, Circuit 348 (P) at A/C damper door switch.

- Is there voltage?

- Yes
Go to C18.

- No
Go to C16.

C16 CHECK B+ AT FUSE OUTPUT

- Using a voltmeter, check for B+ at output side of Fuse 5 (15A).

- Is there B+?

- Yes
Service circuit 298 (P/O) for open circuit. Restore vehicle. Retest system.

- No
Go to C17

C17 CHECK CIRCUIT 298 (P/O) FOR SHORT

- Using an ohmmeter, connect one lead to output side of Fuse 5 (15A). Connect second lead to a known good ground.
- Disconnect electrical connector to A/C damper door switch.

- Is there continuity?

- Yes
Service circuit 298 (P/O) for short to ground. Replace Fuse 5 (15A). Restore vehicle. Retest system.

- No
Go to C18.

C18 CHECK A/C DAMPER DOOR SWITCH MAX A/C POSITION

- Engine off and ignition switch in RUN position.
- A/C control at MAX A/C.
- Reconnect A/C damper door switch electrical connector.
- Rotate A/C damper door switch to MAX A/C position.
- Using a voltmeter, check voltage at Pin 4, Circuit 348 (P).

- Is there voltage?

- Yes
Go to C19

- No
Replace A/C damper door sqitch. Restore vehicle. Retest system

C19 CHECK A/C DAMPER DOOR SWITCH A/C POSITION

- Engine off and ignition switch in RUN position.
- A/C control at MAX A/C.
- Reconnect A/C damper door switch electrical connector.
- Rotate A/C damper door switch to A/C position.
- Using a voltmeter, check voltage at Pin 4, Circuit 348 (P).

- Is there voltage?

- Yes
Go to C5.

- No
Replace A/C damper door switch. Restore vehicle. Retest system.