SERVICE MANUAL UPDATE SEC. 8A A/C COMPRESSOR CONTROLS

SUBJECT: SERVICE MANUAL UPDATE A/C COMPRESSOR CONTROLS REVISED WIRING

MODELS/YEARS: 1991 CUTLASS CIERA AND CUTLASS CRUISER W/3.3L (VIN N) ENGINE

The following pages reflect changes that were made to the A/C compressor control wiring for the 1991 Cutlass Ciera and Cutlass Cruiser with the 3.3L (VIN N) engine and the Four Seasons air conditioning (C60) option.

Please note this information in your copies of the 1991 Cutlass Ciera and Cutlass Cruiser Service Manual on pages 8A-64-2, 8A-64-7, and 8A-64-8.

C60, FOUR SEASON

C1. Measure the voltage at terminal E of the A/C Compressor Control Relay with a fused jumper connected across the terminals of the A/C Low Pressure Cut-Out Switch connector (disconnected).

- If battery voltage is not present, go to C2.

- If battery voltage is present, refer to Section 1B to check for normal refrigerant pressure. If the refrigerant pressure is normal, replace the A/C Low Pressure Cut-Out Switch.

C2. With a fused jumper connected across the terminals of the A/C High Pressure Cut-Off Switch connector (disconnected), measure the voltage at terminal E of the A/C Compressor Control Relay.

- If battery voltage is present, replace the A/C High Pressure Cut-Off Switch.

- If the battery voltage is not present, check the wiring between the switch back to the Heater-A/C Control Assembly (see schematic).

SYSTEM DIAGNOSIS

V6 VIN N

- Use the isolation Tests below to choose the proper diagnostic tests.

- Tests follow the isolation Test.

ISOLATION TEST (TABLE 1)

Measure: VOLTAGE At: A/C COMPRESSOR CONTROL RELAY CONNECTOR (Disconnected) Conditions: - Ignition Switch: RUN (Engine not running) - Mode Selector: NORM - Temperature Outside Car: ABOVE 60 F (16 C)

Measure Correct For Diagnosis Between Voltage ----------- ------- -------------- A (PNK/BLK) Battery Do Test C & Ground If battery voltage is not present,check

F (PNK/BLK) Battery the ENG/ A/C & Ground Fuse and PNK/BLK (639) wires for an open.

- If both voltages are correct, leave the A/C Compressor Control Relay disconnected and go to Table 2.

ISOLATION TEST (TABLE 2)

Connect: FUSED JUMPER At: A/C COMPRESSOR CONTROL RELAY CONNECTOR (Disconnected) Conditions: - Ignition Switch: RUN (Engine not running) - Mode Selector: NORM - Temperature Outside Car: ABOVE 60 F (16 C)

Jumper Between Correct Result For Diagnosis ----------- --------------- -------------- A (PNK/BLK) A/C &E(DK Compressor Do Test B GRN) Clutch engages

- If the result is correct, do Test A.

A: ECM COMPRESSOR CONTROL TEST (TABLE 1) --------------------------------------- Measure: VOLTAGE At: ECM CONNECTORS C1 & C3 (Disconnected) Conditions: - Ignition Switch: RUN (Engine not running) - Mode Selector: NORM - Temperature Outside Car: ABOVE 60 F (16 C) - A/C Compressor Control Relay: RECONNECTED

Measure Correct For Diagnosis Between Voltage ---------- -------- ------------- C1/C9 (LT BLU) & Battery See 1 Ground

C60, FOUR SEASON

Jumper Between Correct Result For Diagnosis ------------ -------------- ------------- A/C A (PNK/BLK) Compressor Do Test B & E (DK GRN) Clutch engages

- If the result is correct, do Test A.

A: ECM COMPRESSOR CONTROL TEST (TABLE 1) ----------------------------------------- Measure: VOLTAGE At: ECM CONNECTORS C1 & C3 (Disconnected) Conditions: - Ignition Switch: RUN (Engine not running) - A/C Mode: NORM - Temperature Outside Car: Above 16 C (60 F) - A/C Compressor Control Relay: RECONNECTED

Measure Correct For Diagnosis Between Voltage ---------- ------- ------------- C1/C9 (LT BLU) & Battery See 1 Ground

C3/F8 (LT GRN/BLK) & Battery See 2 Ground

- If both voltages are correct, go to Table 2.

1. Check for an open in the LT BLU (67) wire.

2. Check for an open in the LT GRN/BLK (366) wire. If wire is good, replace the A/C Compressor Control Relay.

A: ECM COMPRESSOR CONTROL TEST (TABLE 2) ----------------------------------------- Measure: RESISTANCE At: ECM CONNECTOR C1 (Disconnected) Conditions: - Ignition Switch: OFF - Negative Battery Terminal: DISCONNECTED

Measure Correct Between Resistance For Diagnosis ---------------- ---------------- ---------------- D12 (LT BLU/ORN) Infinite (open See 1 & Ground circuit)

- If resistance is correct, go to Table 3.

1. Check that Idle Speed Power Steering Pressure Switch is open. If it is closed, replace it. Check for a short to ground in the LT BLU/ORN (495) wire.

A: ECM COMPRESSOR CONTROL TEST (TABLE 3) --------------------------------------- Connect: FUSED JUMPER At: ECM CONNECTOR C3 (Disconnected) Conditions: - Ignition Switch: RUN (Engine not running) - A/C Mode: NORM - Temperature Outside Car: Above 16 C (60 F)

Jumper Between Correct Result For Diagnosis ------------- ---------------- -------------- A/C Compressor F8 (LT GRN/ Control Relay BLK) & Ground operates and See 1 A/C Compressor Clutch engages

- If the result is correct, but A/C System does not operate normally, condition is due to an ECM fault. Refer to Section 6E for ECM diagnostic procedures.

1. Replace A/C Compressor Control Relay.

B: A/C COMPRESSOR CLUTCH TEST ----------------------------- Measure: VOLTAGE At: A/C COMPRESSOR CLUTCH CONNECTOR (Disconnected) Conditions: - Ignition Switch: RUN (Engine not running) - A/C Mode: NORM - A/C Compressor Control Relay: DISCONNECTED - A/C Compressor Control Relay terminals A and E jumpered - Temperature Outside Car: Above 16 C (60 F)

Measure Correct For Diagnosis Between Voltage ----------- -------- ---------------- A (DK GRN) Battery See 1 & Ground

A (DK GRN) Battery See 2 & B (BLK)

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