Inspection Procedure 5
INSPECTION PROCEDURE 5: No SoundAudio Amplifier Power Supply Circuit:
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 C-113 in order to check the battery circuit of power supply system to the audio amplifier
1. Disconnect audio amplifier connector C-113, 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 C-113 for loose, corroded or damaged terminals, or terminals pushed back in the connector
Q: Is audio amplifier connector C-113 in good condition?
YES: Go to Step 3
NO: Repair or replace the component(s) Refer to Harness Connector Inspection The speakers should sound
STEP 3 Check the wiring harness between audio amplifier connector C-113 (terminal 6 and 16) and the battery
NOTE: Also check intermediate connector C-29 for loose, corroded, or damaged terminals, or terminals pushed back in the connector If intermediate connectors C-29 is damaged, repair or replace the connector as described in Harness Connector Inspection
Q: Is the wiring harness between audio amplifier connector C-113 (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 C-113 in order to check the ground circuit to the audio amplifier
1. Disconnect audio amplifier connector C-113, 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 C-113 for loose, corroded or damaged terminals, or terminals pushed back in the connector
Q: Is audio amplifier connector C-113 in good condition?
YES: Go to Step 6
NO: Repair or replace the component(s) Refer to Harness Connector Inspection The speakers should sound
STEP 6 Check the wiring harness between audio amplifier connector C-113 (terminal 7 and 17) and ground
Q: Is the wiring harness between audio amplifier connector C-113 (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 radio, CD player and CD changer connector C-116 and audio amplifier connector C-114 for loose, corroded or damaged terminals, or terminals pushed back in the connector
Q: Are radio, CD player and CD changer connector C-116 and audio amplifier connector C-114 in good condition?
YES: Go to Step 8
NO: Repair or replace the component(s) Refer to Harness Connector Inspection The door speaker (LH) should sound
STEP 8 Check the wiring harness between CD player and CD changer connector C-116 (terminals 21, 24, 23, 31, 30 and 22) and audio amplifier connector C-114 (terminals 22, 23, 30, 24 and 31)
Q: Do the speakers sound normally?
YES: The procedure is complete
NO: Repair or replace the audio amplifier