Test Description

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

The number(s) below refer to the step number(s) on the diagnostic table.

Verifies that the body control module (BCM) is providing ground to the horn relay.
Tests for voltage at the battery positive voltage terminal of the horn relay coil.
Tests for voltage at the battery positive voltage terminal of the horn relay switch.
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.
The horn relay control circuit includes the horn slip ring and the horn switch. 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 in Wiring Systems.

Fig 1: Horns Inoperative (1 Of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Horns Inoperative (2 Of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 3: Horns Inoperative (3 Of 3)

Courtesy of GENERAL MOTORS CORP.

Fig 4: Horns - Poor Tone

Courtesy of GENERAL MOTORS CORP.