Inspection Procedure 29: PTC heater switch system <RHD (Except vehicles for Hong Kong and Singapore)>

COMMENTS ON TROUBLE SYMPTOM
If a PTC heater switch signal is not set to the A/C-ECU, the PTC heater switch or the PTC heater switch circuit system may be defective.

PROBABLE CAUSES

  • Malfunction of the PTC heater switch
  • Malfunction of the automatic air conditioner control panel (A/C-ECU)

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-30 PTC heater switch connector

Q. Is the check result normal?

Go to Step 2.

Repair the connector.

STEP 2. Check the PTC heater switch.
Refer to .

Q. Is the refrigerant temperature switch operating properly?
Go to Step 3.
Replace the refrigerant temperature switch.

STEP 3. Voltage measurement at C-30 PTC heater switch connector.

(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the "ON" position.

(3)Voltage between terminal 2 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 5.

Go to Step 4.

STEP 4. Check the wiring harness between C-30 PTC heater switch connector terminal No.2 and the ignition switch (IG2).


note Prior to the wiring harness inspection, check joint connector C-01 and junction block connector C-205 and C-202, and repair if necessary.

  • Check the PTC heater switch power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

STEP 5. Connector check: C-106 A/C-ECU connector

Q. Is the check result normal?

Go to Step 6.

Repair the connector.

STEP 6. Check the wiring harness between C-30 PTC heater switch connector terminal No.1 and C-106 A/C-ECU connector terminal No.26.


  • Check the PTC heater switch earth line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

Repair the wiring harness.