Horn Fails To Sound With Alarm Tripped

Possible Causes are:

• CHECK HORN OPERATION
• JUNCTION BLOCK OPEN HORN RELAY CONTROL CIRCUIT
• BODY CONTROL MODULE OPEN HORN RELAY CONTROL CIRCUIT

1. Push the horn button on the steering wheel. Does the horn operate properly? If yes, go to next step. If no, check for and diagnose related Body Control Module Diagnostic Trouble Codes. If there are no DTCs present, diagnose and repair the horn system. Perform VTSS VERIFICATION TEST 1A  under VERIFICATION TESTS.
2. Remove the BCM from the junction block. Using a 12-volt test light connected to 12 volts, probe the Horn Relay Control circuit at the J/B side of the Junction Block-to-Body Control Module connector. While monitoring the test light, press the horn button on the steering wheel. Did the test light illuminate when the horn button was pressed? If yes, replace the Body Control Module. Perform VTSS VERIFICATION TEST 1A  under VERIFICATION TESTS. If no, replace the junction block. Perform VTSS VERIFICATION TEST 1A  under VERIFICATION TESTS.