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: 1559584  Size: MF
(1)Steering Wheel Control Switch Assembly - Upper Left
(2)Steering Wheel Control Switch Assembly - Upper Right
(3)Horn Switch
(4)C277
(5)Turn Signal/Multifunction Switch