GM Service Manual Online
For 1990-2009 cars only
Figure 1:

Horn Assembly


Object Number: 1492975  Size: MF
(1)I/P Harness
(2)Horn Assembly
Figure 2:

Steering Wheel and Column


Object Number: 856748  Size: LF
(1)Steering Wheel Control Switch Assembly - Upper Left (STW)
(2)Passlock Sensor Connector (w/o BAE)
(3)Ignition Key Alarm Switch
(4)Ignition Lock Cylinder Control Actuator
(5)Ignition Lock Cylinder Control Actuator Connector
(6)Ignition Switch
(7)Ignition Key Cylinder
(8)Steering Wheel Control Switch Assembly - Upper Right (STW)
(9)Horn Switch
(10)Steering Wheel Control Switch Assembly - Lower Right (STW)
(11)C277
(12)Steering Wheel Control Switch Assembly - Lower Left (STW)
(13)Turn Signal/Multifunction Switch