Inspection Procedure 4: Audio illumination does not work normally.

caution

Before replacing the radio and CD player, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM

If the tail lamps illuminate, illumination signal is sent from the heater controller assembly (A/C-ECU) to the radio and CD player. This switches the illumination of the radio and CD player from day mode to night mode. If the mode is switched, the illumination signal line, the heater controller assembly (A/C-ECU) or the radio and CD player may be defective.

PROBABLE CAUSES

Malfunction of combination meter
Malfunction of heater controller assembly (A/C-ECU)
Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Check that the tail lamps illuminate.

Q. Is the check result normal?

	Go to Step 2.

	Diagnose the tail lamps. (Refer to .)

STEP 2. Check the illumination.

When the tail lamps are turned on, check whether the illumination other than the radio and CD player is turned on.

Q. Is the check result normal?

	Go to Step 3.

	Replace the heater controller assembly (A/C-ECU).

STEP 3. Check of short to power supply, short to earth, and open circuit in ILL+ line between radio and CD player connector and heater controller assembly (A/C-ECU) connector

Q. Is the check result normal?

	Go to Step 4.

	Repair the connector(s) or wiring harness.

STEP 4. Retest the system

When the tail lamps illuminate, check that the illumination of the radio and CD player is switched from day mode to night mode.

Q. Is the check result normal?

	The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).

	Replace the radio and CD player.