Diagnostic Routine N
Diagnostic Routine N
Diagnostic Overview
The Air Conditioning (AC) Is Always On - AC Compressor Does Not Cycle
Refer to Wiring Diagram Set 55 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
REFER to Controls and Compressor Cycling.
Visual Inspection and Diagnostic Pre-checks
- Inspect the A/C (Air Conditioning) clutch relay.
Pinpoint Test
1. CHECK FOR A/C (Air Conditioning) CLUTCH OPERATION WITH THE A/C (Air Conditioning) CLUTCH RELAY DISCONNECTED
1. Disconnect: A/C (Air Conditioning) Clutch Relay
2. KOER (Key ON Engine Running).
Is the A/C (Air Conditioning) compressor on?
2. CHECK THE POWER CIRCUIT TO THE A/C (Air Conditioning) COMPRESSOR CLUTCH FOR A SHORT TO POWER
1. Ignition OFF.
2. Disconnect: A/C (Air Conditioning) Clutch Relay.
3. Disconnect: A/C (Air Conditioning) Compressor Clutch Field Coil.
4. Measure:
Is any voltage present?
3. CHECK THE A/C (Air Conditioning) COMPRESSOR CLUTCH AIR GAP
1. Measure the A/C (Air Conditioning) compressor clutch air gap at 3 equally spaced locations between the clutch hub and the A/C (Air Conditioning) compressor clutch pulley.
Is the A/C (Air Conditioning) compressor clutch air gap less than 0.6 mm (0.0236 in)?
4. CHECK THE A/C (Air Conditioning) RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Disconnect: A/C (Air Conditioning) Clutch Relay.
3. Disconnect: PCM (Powertrain Control Module) C175B.
4. Measure:
Is the resistance greater than 10,000 ohms?
5. CHECK FOR CORRECT PCM (Powertrain Control Module) OPERATION
1. Ignition OFF.
2. Disconnect and inspect all the PCM (Powertrain Control Module) connectors.
3. Repair:
- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary
4. Reconnect the PCM (Powertrain Control Module) connectors. Make sure they seat and latch correctly.
5. Operate the system and determine if the concern is still present.
Is the concern still present?
