FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Inspection Procedure 5




Inspection Procedure 5: Audio illuminations does not work normally.

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














OPERATION

- When the position light is illuminated, the audio illumination is switched to the nighttime illumination.
- When the brightness is adjusted using the combination meter rheostat switch, the audio illumination brightness is also adjusted.

COMMENTS ON TROUBLE SYMPTOM

The center panel unit, radio and CD player, combination meter, or communication line from the radio and CD player to the combination meter may have a problem.

PROBABLE CAUSES

- The combination meter may be defective.
- The radio and CD player may be defective.
- The center panel unit may be defective.
- Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Operation check of the center panel unit

Operate the audio control switch of the center panel unit, and check if the audio operates normally.

Q. Is the check result normal?

YES Go to Step 2.
NO Refer to Inspection Procedure 4 "The audio does not operate normally by operating the radio and CD player of the center panel unit." Inspection Procedure 4.
STEP 2. Check the combination meter.

Check whether the combination meter works normally.

Q. Is the check result normal?

YES Go to Step 3.
NO Diagnose the combination meter (Refer to Combination Meter).
STEP 3. Using scan tool MB991958, read the combination meter diagnostic trouble code.

Check again if the DTC is set to the combination meter.





(1)
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

Connect scan tool MB991958. Refer to "How to connect scan tool Reading and Clearing Diagnostic Trouble Codes".
(2)Turn the ignition switch to the "ON" position.
(3)Check for combination meter DTCs.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Diagnose the combination meter (Refer to Combination Meter).

NO Go to Step 4.

STEP 4. Check center panel unit connector C-124 and combination meter connector C-04 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Are center panel unit connector C-124 and combination meter connector C-04 in good condition?

YES Go to Step 5.
NO Repair the connector concerned.
STEP 5. Check the wiring harness between center panel unit connector C-124 (terminal 16) and combination meter connector C-04 (terminal 23).

- Check the power supply line for open circuit and short circuit.

NOTE:
Also check A/C control panel connector C-123 [vehicles with A/C] or heater control panel connector C-138 [vehicles without A/C] for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If A/C control panel connector C-123 [vehicles with A/C] or heater control panel connector C-138 [vehicles without A/C] is damaged, repair or replace the connector as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between center panel unit connector C-124 (terminal 16) and combination meter connector C-04 (terminal 23) in good condition?

YES Go to Step 6.
NO Repair the wiring harness.
STEP 6. Check A/C control panel connector C-123 [vehicles with A/C] or heater control panel connector C-138 [vehicles without A/C] for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is A/C control panel connector C-123[ vehicles with A/C] or heater control panel connector C-138[ vehicles without A/C] in good condition?

YES Go to Step 7.
NO Repair the connector concerned.
STEP 7. Check the wiring harness between A/C control panel connector C-123 [vehicles with A/C] or C-138 heater control panel connector [vehicles without A/C] (terminal 8) and combination meter connector C-04 (terminal 22).

- Check the wiring harness for open circuit and short circuit.

Q. Is the wiring harness between A/C control panel connector C-123[ vehicles with A/C] or heater control panel connector C-138[ vehicles without A/C] (terminal 8) and combination meter connector C-04 (terminal 22) in good condition?

YES Go to Step 8.
NO Repair the wiring harness.
STEP 8. Check the wiring harness between A/C control panel connector C-123 [vehicles with A/C] or C-138 heater control panel connector [vehicles without A/C] (terminal 10) and center panel unit connector C-124 (terminal 10).

- Check the wiring harness for open circuit and short circuit.

Q. Is the wiring harness between A/C control panel connector C-123[ vehicles with A/C] or C-138 heater control panel connector[ vehicles without A/C] (terminal 10) and center panel unit connector C-124 (terminal 10) in good condition?

YES Go to Step 9.
NO Repair the wiring harness.
STEP 9. Check radio and CD player connector C-109 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is radio and CD player connector C-109 in good condition?

YES Go to Step 10.
NO Repair the connector concerned.
STEP 10. Check the wiring harness between center panel unit connector C-124 (terminal 4) and radio and CD player connector C-109 (terminal 9).

- Check the communication lines for open circuit and short circuit.

Q. Is the wiring harness between center panel unit connector C-124 (terminal 4) and radio and CD player connector C-109 (terminal 9) in good condition?

YES Go to Step 11.
NO Repair the wiring harness.
STEP 11. Replace the A/C control panel connector [vehicles with A/C] or heater control panel connector [vehicles without A/C] temporarily, and check the trouble symptom.

Replace the A/C control panel connector [vehicles with A/C] or heater control panel connector [vehicles without A/C] temporarily, and check that the audio illumination works normally.

Q. Is the check result normal?

YES Replace the A/C control panel connector [vehicles with A/C] or heater control panel connector [vehicles without A/C].
NO Go to Step 12.
STEP 12. Replace the center panel unit temporarily, and check the trouble symptom.

Replace the center panel unit temporarily, and check that the audio illumination works normally.

Q. Is the check result normal?

YES Replace the center panel unit.
NO Replace the radio and CD player.