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.

2. Listen for an audible click when the headlamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
4. Tests for voltage at the coil side of the headlamp relay. The LP Park fuse supplies power to the coil side feed of the headlamp relay.
5. Verifies that the BCM is providing ground to the headlamp relay.
6. Tests if ground is constantly being applied to the headlamp relay.

Fig 1: Identifying DTC B2577 Diagnostic Table (1 Of 2)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Identifying DTC B2577 Diagnostic Table (2 Of 2)

Courtesy of GENERAL MOTORS CORP.