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

OnStar® Component Locations


Object Number: 623162  Size: MF
(1)Global Positioning Satellite (GPS) Antenna
(2)Cellular Telephone Microphone
(3)Global Positioning System (GPS)
(4)Junction Block-Body
(5)Vehicle Communication Unit (VCU)
(6)OnStar® Button Assembly
(7)Vehicle Interface Unit (VIU)
Figure 2:

LH Front of Vehicle


Object Number: 310802  Size: MF
(1)Upper Radiator Support (Tie Bar)
(2)Headlamp Assembly-LF
(3)Headlamp - High Beam - Left Connector
(4)Daytime Running Lamp (DRL)-Left
(5)Daytime Running Lamp (DRL)-Left Socket
(6)Windshield Washer Reservoir
(7)Park/Turn Signal Lamp Socket-LF
(8)Marker Lamp Socket-LF
(9)Marker Lamp-LF
(10)Park/Turn Signal Lamp-LF
(11)Snowplow (Option) Connector C125
(12)Headlamp Connector-Low Beam-Left
(13)Marker Lamp-LF
Figure 3:

Junction Block-Underhood


Object Number: 310806  Size: MF
(1)Junction Block-Underhood Bracket
(2)Inflatable Restraint Harness
(3)Radiator Support
(4)Inline Connector-C101 (IP Harness Side)
(5)Inline Connector-C101 (Forward Lamp Harness Side)
(6)LH Battery Tray
(7)Junction Block-Underhood Bracket
(8)Junction Block-Underhood
Figure 4:

Below the Underhood Junction Block


Object Number: 413351  Size: MF
(1)Inline Connector-C102
(2)Junction Block-Underhood Support/Mount
(3)Inline Connector-C152
(4)Inline Connector-C100
Figure 5:

Lower LF of the Engine Components (6.6L)


Object Number: 768351  Size: MF
(1)Engine - 6.6L Diesel
(2)Negative Battery Cable
(3)Negative Battery Ground
(4)G103
(5)Engine Harness
Figure 6:

Lower Right Side of the Engine (6.6L)


Object Number: 768355  Size: MF
(1)Engine - 6.6L Diesel
(2)Engine Harness
(3)G102
(4)Auxiliary Negative Battery Ground
(5)Starter Relay Terminal
(6)Starter Solenoid
Figure 7:

LR of the Engine Splices (6.6L)


Object Number: 777029  Size: MF
(1)Engine - Diesel (6.6L)
(2)S118
(3)S119
Figure 8:

Instrument Panel Harness Routing View


Object Number: 574009  Size: LF
(1)Instrument Panel
(2)Instrument Panel Cluster Connector
(3)Sunload Sensor
(4)Radio Connectors
(5)Daytime Running Lamps (DRL) Sensor
(6)Air Temperature Sensor - Upper
(7)Passenger Inflatable Restraint Module Connector
(8)Inflatable Restraint Module Switch Connector
(9)Inline Connector C206 (HVAC Auto A/C)
(10)Inline Connector C207 (RTD)
(11)Speaker Connector
(12)Compartment Lamp Connector
(13)Fuse Block-Right I/P
(14)Inline Connector to RH Door Harness
(15)Inline Connector to RH Body Harness (06 only)
(16)Ashtray Lamp Connector
(17)HVAC Control Module Connectors
(18)Cigarette Lighter Connector
(19)Power Accessary Connectors
(20)Inline Connector C351 (LH Body Harness Side)
(21)Console Connector (Y91 only)
(22)Steering Column Connector
(23)Inline Connector C307 (Console Extension Harness Side)
(24)Body Control Module Connectors
(25)Cargo/Fog Switch Connector
(26)Headlamp Switch Connector
(27)Steering Column (SIR) Connector
(28)Fuse Block-Left I/P
(29)Data Link Communication Connector
(30)Inflatable Restraint Sensing And Diagnostic Module (SDM) Connector
(31)Inline Connector C204
(32)Inline Connector C200 (LH Door Harness)
(33)Footwell Courtesy Lamp - Left
(34)Body Wiring Harness Junction Block
(35)Splice Pack 203 (SP203)
(36)Inline Connectors to Automatic Transfer Case (C151, C153)
(37)Inline Connector C102 (I/P to Chassis Harness)
(38)Inline Connector C103 (I/P to Forward Lamp Harness)
(39)Junction Block-Underhood
(40)Instrument Panel Battery Feed Connectors
(41)Trailer Power Feed Connector
(42)Cruise Control/Throttle Actuator Connector
(43)Underhood Lamp Connector
(44) Speaker - Left Connector
(45)Inline Connector C204 (I/P to LH Body Harness)
(46)Underhood Lamp Ground
(47)I/P Harness to Plenum Ground
(48)Windshield Wiper System Module Connector
Figure 9:

Instrument Cluster


Object Number: 310124  Size: MF
(1)Instrument Panel Cluster (IPC)
(2)Inline Connector C202 M
(3)Inline Connector C202 F
(4)Instrument Cluster Electrical Connector
(5)Instrument Panel Carrier
(6)Instrument Panel
Figure 10:

Lower Steering Column Connectors


Object Number: 310109  Size: MF
(1)Inline Connectors (C201A, C201B and C201C)
(2)Inline Connector C201
(3)Inflatable Restraint Harness
(4)Inflatable Restraint Electrical Connector
(5)Body Control Module (BCM) Bracket
(6)Body Control Module (BCM) Harness
(7)A/T Shift Lock Control Solenoid Connector
(8)A/T Shift Lock Control Solenoid Electrical Connector
(9)Lower Steering Column Shaft
(10)Inflatable Restraint Steering Wheel Module Connector with Tether
(11)Instrument Panel Bracket
Figure 11:

Center Console Wiring (1 of 2)


Object Number: 656698  Size: MF
(1)Front Floor Compartment Bezel
(2)Inline Connector-C249
(3)Inline Connector-C340( I/P Harness Side)
(4)Inline Connector-C340 (Rear Console Harness Side)
Figure 12:

Front of the Center Console


Object Number: 656701  Size: MF
(1)Inline Connector-306 (IP Harness Side)
(2)Inline Connector-306 (Front Floor Console Harness Side)
(3)Inline Connector-C249 (IP Harness Side)
(4)Inline Connector-C307 (Uplevel Utility) 0r C340 (Luxury Utility)
(5)Front Floor Console
Figure 13:

Center Console Wiring (2 of 2)


Object Number: 623128  Size: MF
(1)Front Floor Compartment
(2)I/P Harness
(3)Inline Connector 307 (Uplevel Utility), Inline 340 (Luxury Utility)
(4)Inline Connector 307 (Uplevel Utility), Inline 340 (Luxury Utility)
(5)Console Harness
(6)Inline Connector 314 (Rear Console Harness Side)
(7)Inline Connector 314 (LH body Harness Side)
Figure 14:

Behind the Center of the I/P


Object Number: 623121  Size: MF
(1)Instrument Panel
(2)Radio Connectors
(3)Console Extension Harness
(4)Inline Connector 253 (IP Harness Side)
(5)Inline Connector 253 (Console Extension Harness Side)
(6)Compact Disc Player Connector
(7)Front Floor Console Extension
(8)Instrument Panel Harness
(9)Radio
Figure 15:

HVAC Module Assembly (Connections)


Object Number: 310004  Size: MF
(1)Recirculation Actuator Connector
(2)Instrument Panel
(3)Electrical Harness Connector
(4)Ground 200 (G200)
(5)Blower Motor Resistor Assembly
(6)Blower Motor Resistor Connector
(7)Harness Inline Connector (C296)
(8)Air Temperature Actuator Connector
(9)Air Temperature Actuator
(10)Mode Actuator
Figure 16:

Headliner Harness to Junction Block-Body


Object Number: 623107  Size: MF
(1)A-Pillar
(2)Headliner Wiring Harness
(3)Junction Block-Body
(4)Headliner Harness Connector C-6
Figure 17:

Left Kick Panel (1 of 2)


Object Number: 310055  Size: MF
(1)C200 (IP Harness Side)
(2)C204
(3)A-Pillar
(4)C200 (Door Harness Side)
Figure 18:

Left Kick Panel (2 of 2)


Object Number: 623154  Size: MF
(1)LH Dash Panel Insulator
(2)Door Wiring Harness -LH
(3)Inline Connector C205 (Door Harness Side)
(4)Inline Connector C205 (LH Body Wiring Harness Side)
(5)Inline Connector C204 (LH Body Wiring Harness Side)
(6)Body Wiring Harness-LH
(7)Inline Connector C204 (I/P Harness Side)
(8)Body Harness-LH
Figure 19:

Right Kick Panel (2 of 2)


Object Number: 617242  Size: MF
(1)Side Cowl Panel
(2)C299 (Door Harness Side) -- Uplevel
(3)C299 (I/P Harness Side) -- Uplevel
(4)C208 (Right Body Harness Side)
(5)C208 ( I/P Harness Side)
Figure 20:

Right Kick Panel (1 of 2)


Object Number: 656720  Size: MF
(1)Junction Block-I/P
(2)Junction Block-I/P Connector-C2 (RF Door Harness)
(3)RF Door Harness
(4)Inline Connector-C304 (Passenger Heated Seat)
(5)Inline Door Harness Connector-C299 (Uplevel) Utility
Figure 21:

LR of the Cab Components (Extended Cab Pickup)


Object Number: 309982  Size: MF
(1) Side Inner Body Panel - LH
(2)Panel Access Hole
(3) Speaker - LR Connector (Harness Side)
(4)Speaker - LR Connector (Speaker Side)
(5)Body Wiring Harness
(6)Body Wiring Harness
(7)Rear Glass (Defogger Grid Not Shown)
(8)Rear Defogger Grid Connector (Harness Side)
(9)Rear Defogger Grid Connector (Window Side)
Figure 22:

Below the RR Seat (Utility)


Object Number: 741070  Size: MF
(1)Rear Seat
(2)Rear Seat Harness Connector (Inline C349)
(3)Right Body Harness Connector (Inline C349)
(4)Body Harness
Figure 23:

Rear HVAC Harness


Object Number: 573929  Size: LF
(1)Inner Body Side Panel
(2)Splice Pack 410 (SP410)
(3)Splice Pack 410A (SP410A)
(4)Blower Motor Connector
(5)Auxiliary HVAC Assembly - Rear Auxiliary
(6)Air Temperature Sensor-Lower Auxiliary
(7)Mode Actuator Connector
(8)Inline Connector 350 (Auxiliary HVAC Harness Side)
(9)Inline Connector 350 (Headliner Harness Side)
(10)Inline Connector 397 (Auxiliary HVAC Harness Side)
(11)Inline Connector 397 (RH Body Harness Side)
Figure 24:

RR D-Pilar Wiring (Utility)


Object Number: 574004  Size: MF
(1)Back Body Opening Inner Upper Panel
(2)CHSML Cargo
(3) Door Lock Switch Rear Cargo
(4)Splice Pack 410
(5)Speaker - RR Connector
(6)Inline to Headliner
Figure 25:

LR D-Pillar Wiring (Utility)


Object Number: 574001  Size: LF
(1)Body Side Inner Panel
(2)Body Harness-LH
(3)Speaker- Subwoofer Connector
(4)Speaker-LR (D Pillar)
Figure 26:

Rear of the Frame


Object Number: 615821  Size: MF
(1)Inline Connector C405 to Tail Lamp Harness
(2)Shock Absorber Solenoid Connector-RR
(3)Frame
(4)Inline Connector C450
(5)Chassis Harness
Figure 27:

Chassis Wiring Harness to Front Frame (25 Series 3/4 ton)


Object Number: 615810  Size: MF
(1)Shock Absorber Solenoid-LF Connector
(2)Wheel Speed Sensor (WSS)-LF Connector
(3)Wheel Speed Sensor (WSS)-LF Connector
(4)Suspension Position Sensor-LF Connector
(5)Suspension Position Sensor-LF Connector
(6)Chassis Harness
(7)Shock Absorber Solenoid-RF Connector
(8)Shock Absorber Solenoid-RF Connector
(9)Suspension Position Sensor-RF Connector
(10)Frame
Figure 28:

RR of the Frame (RTD)


Object Number: 615767  Size: MF
(1)Inline Connector C450 (Chassis Harness Side)
(2)Inline Connector C450 (Body Harness Side)
(3)Frame
Figure 29:

RR Frame -- Lighting Components


Object Number: 623153  Size: MF
(1)Back Body Opening Lower Frame
(2)Rear Lamp Wiring Harness
(3)Inline Connector 403 (Rear Lamp Harness Side)
(4)Inline Connector 403 (Tail Lamp Harness Side)
(5)Inline Connector 404 (Rear Lamp Harness Side)
(6)Inline Connector 404 (Rear License Plate Harness Side)
(7)License Plate Wiring Harness
Figure 30:

Liftgate Wiring Harness to Liftgate


Object Number: 573926  Size: LF
(1)Liftgate with Liftglass
(2)Liftglass Defog Connector
(3)Liftgate Latch Connector
(4)Liftgate Lower Latch Connector
(5)Liftgate Latch Connector
(6)Liftgate Lower Latch Connector
(7)Liftgate Latch Connector
(8)Wiper Motor Connector
(9)Inline Connector C499