Horn Diagnostic System Check

Connect scan tool to Data Link Connector (DLC). DLC is located on left side of instrument panel, near steering column. If scan tool powers up, go to next step. If scan tool does not power up, go to TEST A: SCAN TOOL DOES NOT POWER UP under SYSTEM TESTS.
Turn ignition switch to RUN position. Attempt to establish communication with Body Control Module (BCM). If scan tool communicates with BCM, go to next step. If scan tool does not communicate with BCM, go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS.
Select DISPLAY DTCs function on scan tool for BCM. If any DTCs are retrieved, go to next step. If no DTCs are retrieved, diagnose and repair horn system concern. See STEERING COLUMN SWITCHES article.
If communication DTCs (DTCs beginning with a "U") are not retrieved, go to next step. If any DTCs beginning with "U" are retrieved, go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS.
If DTC B1000 is not retrieved, go to next step. If DTC B1000 is retrieved, go to DTC B1000: BODY CONTROL MODULE MALFUNCTION under DIAGNOSTIC TESTS.
If DTC B1328 is retrieved:
- On 2001 models, see GENERATORS & REGULATORS article in ELECTRICAL.
- On 2002 models, see GENERATORS & REGULATORS article in ELECTRICAL.
If DTC B1328 is not retrieved, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS .