INSPECTION PROCEDURE N-2: Theft-alarm system: Horn does not sound when the theft-alarm is triggered.: Diagnosis

Required Special Tool: 

• MB991223: Test Harness Set

1. STEP 1. Verify the keyless entry system horn answerback. 

   Activate the keyless entry system horn answerback. (Refer to Keyless Entry System - On-vehicle Service - ENABLING/DISABLING THE ANSWERBACK FUNCTION .)

   Q: Does the horn answerback function work? 

   YES  : Replace the ETACS-ECU. The horn should sound when the theft-alarm system is triggered.

   NO:  Go to Step 2.

2. STEP 2. Check the theft-alarm horn. 

   Connect the battery as shown and check that the theft-alarm horn sounds. See Fig 1.

   Q: Is the theft-alarm horn in good condition? 

   YES  : Go to Step 3.

   NO:  Replace it. The horn should sound when the theft-alarm system is triggered.

   Fig 1: Checking Theft-Alarm Horn Sounds

   Courtesy of DAIMLERCHRYSLER CORPORATION
3. STEP 3. Check the theft-alarm horn relay. 
   TESTER CONNECTION SPECIFIED CONDITION CHART
   
   

   BATTERY VOLTAGE	TESTER CONNECTION	SPECIFIED CONDITION
   Not applied	1 - 4	Open circuit
   Connect terminal 2 to the positive battery terminal Connect terminal 3 to the negative battery terminal	1 - 4	Less than 2 ohms

   Fig 2: Identifying Theft-Alarm Horn Relay Connector A-06X

   Courtesy of DAIMLERCHRYSLER CORPORATION

   Q: Is the theft-alarm horn relay in good condition? 

   YES  : Go to Step 4.

   NO:  Replace it. The horn should sound when the theft-alarm system is triggered.

   Fig 3: Checking Theft-Alarm Horn Relay Circuit

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4. STEP 4. Check the theft-alarm horn relay power supply circuit at the theft-alarm horn relay connector A-06X. 
   1. Disconnect the theft-alarm horn relay connector A-06X and measure at the relay box side.
      Fig 4: Identifying Theft-Alarm Horn Relay Connector A-06X

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   2. Measure the voltages between terminals 1, 2 and ground.
      • The voltage should equal approximately 12 volts (battery positive voltage).

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

   YES  : Go to  Step 7.

   NO:  Go to Step 5.

   Fig 5: Measuring Voltages Between Terminals 1, 2 And Ground

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5. STEP 5. Check the theft-alarm horn relay connector A-06X for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Is theft-alarm horn relay connector A-06X in good condition? 

   YES  : Go to Step 6.

   NO:  Repair or replace the damaged component(s). Refer to , HARNESS CONNECTOR INSPECTION . The theft-alarm horn should sound when the theft-alarm system is triggered.

   Fig 6: Identifying Theft-Alarm Horn Relay Connector A-06X

   Courtesy of DAIMLERCHRYSLER CORPORATION
6. STEP 6. Check the wiring harness between theft-alarm horn relay connector A-06X (terminal 1 and 2) and fusible link (4). 

   Q: Are the wiring harness between theft-alarm horn relay connector A-06X (terminal 1 and 2) and fusible link (4) in good condition? 

   YES  : No action is necessary and testing is complete.

   NO:  The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. The horn should sound when the theft-alarm system is triggered.

   Fig 7: Identifying Theft-Alarm Horn Relay Connector A-06X (Fusible Link 4)

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7. STEP 7. Check the theft-alarm horn relay connector A-06X and ETACS-ECU connector C-317 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Are theft-alarm horn relay connector A-06X and ETACS-ECU connector C-317 in good condition? 

   YES  : Go to Step 8.

   NO:  Repair or replace the damaged component(s). Refer to , HARNESS CONNECTOR INSPECTION . The horn should sound when the theft-alarm system is triggered.

   Fig 8: Identifying Theft-Alarm Horn Relay Connector A-06X

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   Fig 9: Identifying ETACS-ECU Connector C-317

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8. STEP 8. Check the wiring harness between theft-alarm horn relay connector A-06X (terminal 3) and ETACS-ECU connector C-317 (terminal 40). 
   Fig 10: Identifying Connector A-06X

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   Fig 11: Identifying Connector C-317

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   NOTE: Also check intermediate connector C-209 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-209 is damaged, repair or replace it. Refer to , HARNESS CONNECTOR INSPECTION .

   Q: Are the wiring harness between theft-alarm horn relay connector A-06X (terminal 3) and ETACS-ECU connector C-317 (terminal 40) in good condition? 

   YES  : Go to Step 9.

   NO:  The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. The horn should sound when the theft-alarm system is triggered.

   Fig 12: Identifying Connector C-209

   Courtesy of DAIMLERCHRYSLER CORPORATION
9. STEP 9. Check the theft-alarm horn relay connector A-06X and theft-alarm horn connector A-25 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 

   Q: Are theft-alarm horn relay connector A-06X and theft-alarm horn connector A-25 in good condition? 

   YES  : Go to Step 10.

   NO:  Repair or replace the damaged component(s). Refer to , HARNESS CONNECTOR INSPECTION . The horn should sound when the theft-alarm system is triggered.

   Fig 13: Identifying Connector A-06X

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   Fig 14: Identifying Connector A-25 - SEBRING

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   Fig 15: Identifying Connector A-25 - STRATUS

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10. STEP 10. Check the wiring harness between theft-alarm horn relay connector A-06X (terminal 4) and theft-alarm horn connector A-25 (terminal 1). 

    Q: Is the wiring harness between horn relay connector A-06X (terminal 4) and theft-alarm horn connector A-25 (terminal 1) in good condition? 

    YES  : Go to Step 11.

    NO:  The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. The theft-alarm horn should sound when the theft-alarm system is triggered.

    Fig 16: Identifying Connector A-06X

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    Fig 17: Identifying Connector A-25 - SEBRING

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    Fig 18: Identifying Connector A-25 - STRATUS

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11. STEP 11. Check that the theft-alarm horn is installed properly. 
    NOTE: The theft-alarm horn is grounded to the body through the installation bolts.

    Q: Is the theft-alarm horn installation in good condition? 

    YES  : Replace the ETACS-ECU. The horn should sound when the theft-alarm system is triggered.

    NO:  The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. The horn should sound when the theft-alarm system is triggered.