Flowchart No. 3: Magnetic Clutch and Condenser Fan Inop
System Operation
1. Signals from the fan switch and A/C switch are sent to the A/C amplifier.
2. The thermoswitch resistance changes as the evaporator's temperature changes.
3. The A/C amplifier monitors the thermoswitch resistance changes.
4. The A/C amplifier signals the PCM (ECM: MTX) to turn the magnetic clutch on or off based on the evaporator's temperature. This protects the evaporator from freezing.
5. The PCM (ECM: MTX) controls the magnetic clutch by turning the A/C relay on or off.
6. To help liquefy the refrigerant, the condenser fan rotates to increase airflow through the condenser when the A/C compressor is on.
7. If the refrigerant pressure switch is broken or there is abnormal pressure in the refrigerant system, the refrigerant pressure switch will remain open and not allow current to flow to the magnetic clutch and condenser fan.
Step 1
1. Check the following fuses.
2. If the fuses are OK, go to Step 2.
3. If a fuse is burnt, check for a short-circuit in the wiring harness before replacing the fuse.
Step 2
1. Remove the A/C relay.
2. Turn the ignition switch to ON.
3. Measure the voltage at the terminal wires of the A/C relay connector.
Step 3
1. Connect battery positive voltage and check for continuity between the terminals of the A/C relay.
2. If correct, reinstall the A/C relay and go to Step 4.
3. If not as specified, replace the A/C relay.
Step 4
1. Remove the front console.
2. Disconnect the appropriate PCM (ECM: MTX) connector.
3. Connect a jumper wire between the terminal wire (G/W) of the A/C relay connector and ground.
4. Turn the ignition switch to ON, and verify that the magnetic clutch and condenser fan operate.
Step 5
1. Turn the A/C switch on and set the fan switch to the first position.
2. Verify that the A/C switch indicator light illuminates.
Step 6
- Measure the voltage at the following terminal wires of the PCM (ECM: MTX) connector.
Step 7
- Measure the voltage at the following terminal wires of the A/C amplifier.