Inspection Procedure 2

No Sound.

Part 1:

Part 2:

CIRCUIT OPERATION
Power is supplied from the battery directly to the audio amplifier.

TECHNICAL DESCRIPTION (COMMENT)
The cause is probably a faulty audio amplifier power supply circuit system.

TROUBLESHOOTING HINTS
- Damaged wiring harness or connector
- Malfunction of the audio amplifier

DIAGNOSIS

Required Special Tool:
- MB991223: Harness set

STEP 1. Measure the voltage at audio amplifier connector D-41 in order to check the battery circuit of power supply system to the audio amplifier.




1. Disconnect audio amplifier connector D-41, and measure at the wiring harness side.




2. Measure the voltage between terminal 6 and ground.
- The voltage should measure approximately 12 volts (battery positive voltage).

3. Measure the voltage between terminal 16 and ground.
- The voltage should measure approximately 12 volts (battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery positive voltage)?

YES: Go to Step 4.

NO: Go to Step 2.




STEP 2. Check audio amplifier connector D-41 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio amplifier connector D-41 in good condition?

YES: Go to Step 3.

NO: Repair or replace the damaged components). Refer to Harness Connector Inspection. The speakers should sound.







STEP 3. Check the wiring harness between audio amplifier connector D-41 (terminal 6 and 16) and the battery.

NOTE: Also check intermediate connector C-134 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors C-134 is damaged, repair or replace the connector as described in Harness Connector Inspection.

Q: Is the wiring harness between audio amplifier connector D-41 (terminal 6 and 16) and the battery in good condition?

YES: There is no action to be taken.

NO: Repair the wiring harness. The speakers should sound.

STEP 4. Measure the resistance at audio amplifier connector D-41 in order to check the ground circuit to the audio amplifier.




1. Disconnect audio amplifier connector D-41, and measure at the wiring harness side.




2. Measure the resistance between terminal 7 and ground.
- The resistance should be 2 ohms or less.

3. Measure the resistance between terminal 17 and ground.
- The resistance should be 2 ohms or less.

Q: Is the measured resistance 2 ohms or less?

YES: Go to Step 7.

NO: Go to Step 5.




STEP 5. Check audio amplifier connector D-41 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio amplifier connector D-41 in good condition?

YES: Go to Step 6.

NO: Repair or replace the damaged component(s). Refer to Harness Connector Inspection. The speakers should sound.




STEP 6. Check the wiring harness between audio amplifier connector D-41 (terminal 7 and 17) and ground.

Q: Is the wiring harness between audio amplifier connector D-41 (terminal 7 and 17) and ground in good condition?

YES: There is no action to be taken.

NO: Repair the wiring harness. The speakers should sound.

STEP 7. Check the DIN cable between audio amplifier and radio and CD player is connected correctly.

Q: Do the speakers sound normally?

YES: Go to Step 8.

NO: Repair or replace the DIN cable. The door speaker (LH) should sound.

STEP 8. Check the DIN cable between radio and CD player and CD auto changer is connected correctly.

Q: Do the speakers sound normally?

YES: The procedure is complete.

NO: Repair or replace the DIN cable. The door speaker (LH) should sound.