Test Description

WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

4. Verifies that the body control module (BCM) is providing ground to the horn relay.
5. Tests for voltage at the battery positive voltage terminal of the horn relay coil.
7. Tests for voltage at the battery positive voltage terminal of the horn relay switch. The HORN fuse supplies power to the battery positive voltage terminal of the horn relay switch.
15. The horns need maximum current flow to operate properly. A high resistance (greater than 0.5Ω) in the horn control circuit or the horn ground circuit could cause operating problems with the horns. Check the circuits for faults that would restrict current flow.
17. The horn relay control circuit includes the horn slip ring and the horn switch. The horn switch is part of the inflatable restraint steering wheel module. The horn slip ring and the horn switch must be tested for a high resistance, an open or a short to voltage when testing the relay control circuit. Refer to CIRCUIT TESTING and WIRING REPAIRS and REMOVAL & INSTALLATION article.

Fig 1: Identifying Horns Inoperative Diagnostic Table (1 Of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Identifying Horns Inoperative Diagnostic Table (2 Of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 3: Identifying Horns Inoperative Diagnostic Table (3 Of 3)

Courtesy of GENERAL MOTORS CORP.