Air Conditioning Compressor Lock Controller

AIR CONDITIONING COMPRESSOR LOCK CONTROLLER
Operation
1. The A/C compressor lock controller compares compressor rpm with engine rpm to determine if the drive belt is slipping or the compressor has seized. If the rpm difference between the engine and compressor exceed 92% for more than three seconds, the A/C compressor lock controller turns oft the magnetic clutch relay which opens the magnetic clutch circuit.
2. When a signal is received from the ECU requesting compressor operation, the A/C compressor lock controller will energize the magnetic clutch relay to determine if the compressor drive belt is slipping. If the speed difference between the engine and compressor indicates the belt is slipping, the A/C compressor lock controller will de-energize the magnetic clutch relay.

3. If the A/C compressor lock controller senses the compressor drive belt is slipping, it will de-activate the magnetic clutch relay. Also, it will send a signal to the A/C ECU to activate the compressor warning indicator The indicator will blink.
4. The A/C compressor lock controller does not contain a memory circuit. It will operate the compressor and check for belt slippage each time the ignition is turned on and a signal is sent from the ECU indicating the need for compressor operation.

5. The controller is mounted top of the passenger side under cover.

CIRCUIT DIAGRAM
AIR CONDITIONING CONTROL UNIT CIRCUIT

TROUBLESHOOTING HINTS
Air Conditioning Control Unit Inspection
Disconnect the amplifier and inspect the connector on the wire harness side as shown in the chart below.

Test Conditions:
1. Ignition switch: ON
2. Air conditioning switch: ON
3. Temperature control lever: MAX. COOL
4. Blower switch: HI

Air Conditioning Compressor Lock Controller Inspection
Disconnect the amplifier and inspect the connector on the wire harness side as shown in the chart below.

TROUBLESHOOTING QUICK-REFERENCE TABLE

Compressor doesn't operate

Interior temperature does not lower (No cold air coming out)