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

Left Front of Vehicle - Engine Compartment


Object Number: 1654320  Size: MF
(1)Electronic Brake Control Module (EBCM)
Figure 2:

Center of the I/P


Object Number: 826775  Size: LF
(1)Marker Lamp Switch (RQ2 and U86 or RQ3)
(2)Automatic Transmission Fluid Temperature (TFT) Gage (Allison® LCT/UTX)
(3)High Idle Switch (UF3)
(4)Air Brake Pressure Gage (JE4)
(5)Traction Control Switch (NW9)
(6)Outside Heated Mirror Switch (DB6/DB8)
(7)Exhaust Brake Switch (K40)
(8)Rear Axle Driver Control Switch - Two Speed (HPZ/Automatic Transmission)
(9)Inflatable Restraint I/P Module Disable Switch (AK5 w/o AQR)
(10)Air Suspension Dump Switch (G40/G45/GSJ)
(11)Power Take-Off (PTO) Switch
(12)Driver Information Center (DIC)
Figure 3:

Wheel Speed Sensor (WSS) - RF, LF Similar


Object Number: 231740  Size: LF
(1)Wheel Speed Sensor (WSS)
Figure 4:

Wheel Speed Sensor (WSS) - LR, RR similar


Object Number: 231761  Size: MF
(1)Wheel Speed Sensor (WSS) - LR