Check that the fan speed control dial (switch) system is operating normally, and then inspect for the following.
1. Pre-check and visual inspection
1) Inspect the battery voltage.
- If there is a malfunction in the battery voltage, charge or replace the battery.
2) Inspect the fuses.
- If an abnormal condition such as a blowout is found, inspect or repair the cause of the abnormal condition before replacing the fuse.
3) Inspect the ground point.
- If there is a failure with the ground point, repair and clean it.
4) Inspect the harnesses and connectors.
- Inspect for poor connections at the connectors, worn or bent harnesses, or for shorts to other circuits in the wires inside the harness.
5) Check for any interference from aftermarket electronic components.
- Turn OFF or remove any aftermarket electronic components such as two-way radios or lights to ensure that there is no influence on inspections or operations.
2. Components inspection
1) Inspect the A/C fuse.
- If an abnormal condition is found in fuses, inspect or repair the cause of the blowout before replacing the fuses.
2) Inspect the A/C compressor relay.
- Inspect for continuity using a DMM, and replace the relay if a malfunction is found.
3) Inspect the pressure switch.
4) Inspect for continuity using a DMM, and replace the pressure switch if a malfunction is found.
5) Inspect the A/C switch.
- Inspect for continuity using a DMM, and replace the A/C switch if a malfunction is found.
6) Inspect the ECM.
- Observe the DTC information, and replace the ECM if a malfunction is found.
7) Inspect the electronic thermostat.
- Replace the electronic thermostat if a malfunction is found.
8) Inspect the magnetic switch.
- Replace the magnetic clutch if a malfunction is found.
3. Inspection of circuit
1) Inspect the following circuits for abnormal conditions. If an abnormal condition is found, repair or replace.
Each terminal No. indicates the body harness side connector terminal.
- Between the blower motor relay No. 2 terminal and the A/C compressor relay No. 1 terminal
- Between fuse Electrical (IG2) and A/C compressor relay No. 3 terminal
- Between the Fuse Electrical (IG2) and the ECM No. A34 terminal （RZ4E engine models） or between the Fuse Electrical (IG2) and the ECM No. A21 terminal （4JJ3 engine models）
- Between the A/C compressor relay No. 3 terminal and the A/C compressor relay No. 4 terminal
- Between the A/C compressor relay No. 4 terminal and the ECM No. A12 terminal （RZ4E engine models） or between the A/C compressor relay No. 4 terminal and the ECM No. A5 terminal （4JJ3 engine models)
- Between the A/C compressor relay No. 2 terminal and the magnetic clutch
- Between the blower motor relay No. 2 terminal and the pressure switch No. 2 terminal
- Between the pressure switch No. 1 terminal and the electronic thermostat No. 2 terminal
- Between the electronic thermostat No. 1 terminal and ground
- Between the control lever No. 9 terminal and the ground (Manual type)
- CAN communication circuit between the control panel and the ECM (Auto A/C type)