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

Forward Lamp Harness - Left/Right Routing - V22 Shown, GRW Similar


Object Number: 1593957  Size: LF
(1)S144
(2)Core Support
(3)LH Frame Rail
(4)S117
(5)C107 (5 cavities) Chassis Harness to Forward Lamp Harness - Left
(6)C108 (5 cavities) Chassis Harness to Forward Lamp Harness - Right
(7)S143
Figure 2:

Exhaust Brake Harness - K40/NPE


Object Number: 1559010  Size: LF
(1)Radiator Fan Shroud
(2)Exhaust Brake Relay (K40/NPE w/o LLY)
(3)C104 (6 cavities - LG4/LG5/LLY) Engine Chassis Harness to the Exhaust Brake Harness
(4)Exhaust Brake Harness (K40/NPE)
(5)Exhaust Brake Actuator Control Solenoid Valve (K40/NPE)
(6)Exhaust Throttle
(7)Exhaust Brake Actuator (K40/NPE)
Figure 3:

Chassis Front Engine Compartment


Object Number: 1558088  Size: LF
(1)C108 (5 cavities) Chassis Harness to the Forward Lamp Harness - Right
(2)C106 (6 cavities - C4/C5) Radiator Harness to the Chassis Harness or C106 (12 cavities - C6/C7/C8) Chassis Harness to the Radiator Harness
(3)G100
(4)Wheel Speed Sensor (WSS) - RF Connector
(5)C100 (30 cavities) Chassis Harness to the Engine Harness
(6)C126 (40 cavities) Chassis Harness to I/P Harness
(7)Brake Fluid Level Switch (JE3)
(8)Power Brake (P/B) Booster Fluid Flow Switch (JE3)
(9)Hydromax® Relay (JE3)
(10)C410 (3 cavities) Chassis Harness to Air Compressor Harness (K16)
(11)Wheel Speed Sensor (WSS) - LF Connector
(12)Electronic Brake Control Module (EBCM) Connector
(13)C107 (5 cavities) Chassis Harness to Forward Lamp Harness - Left
Figure 4:

A/C Harness Routing - LLY Shown, Others Similar


Object Number: 1593953  Size: LF
(1)A/C Accumulator/Dehydrator
(2)C105 Engine Harness to A/C Harness
(3)A/C Compressor Clutch Diode
(4)A/C Compressor Clutch Relay
Figure 5:

A/C Compressor Harness - L18 Shown, Others Similar


Object Number: 1557644  Size: LF
(1)A/C Compressor Harness
(2)A/C High Pressure Switch Connector
(3)A/C Compressor
(4)S148
(5)A/C Compressor Clutch Diode
(6)A/C Compressor Clutch Connector
(7)Engine Harness
(8)S147
(9)A/C Compressor Clutch Relay
(10)A/C Low Pressure Switch Connector
Figure 6:

Connectors C118 and C119


Object Number: 1195994  Size: LF
(1)C118 (40 cavities) Engine Harness to the Engine Chassis Harness
(2)C119 (24 cavities) Engine Harness to the Engine Chassis Harness
Figure 7:

Battery Cable Harness Routing (L18/TNL/TNN)


Object Number: 1593954  Size: LF
(1)LH Frame Rail
(2)Junction Block - Underhood
(3)G100
(4)Battery Box
Figure 8:

Back Right of the Engine Compartment (L18)


Object Number: 822091  Size: LF
(1)C101
(2)C124
(3)Engine Harness
(4)C124
(5)I/P Harness
(6)C101
Figure 9:

Engine Chassis Harness - 1 of 2 (LLY)


Object Number: 1807009  Size: LF
(1)C121
(2)S163
(3)S114
(4)To Underhood Junction Block
(5)S118
(6)Fuse Block - Underhood (Primary)
(7)Engine Control Module C2
(8)Engine Control Module C1
(9)Transmission Control Module (TCM) (w/A/T)
(10)Mass Aif Flow/ Intake Air Temperature (MAF/IAT) Sensor
(11)C105
(12)Starter
(13)Turbine Shaft Speed (TSS) Sensor Connector
(14)S166
(15)Vehicle Speed Sensor (VSS) Connector
(16)C175
(17)C100
(18)C102
(19)C124
(20)C101
(21)S107
(22)S121
(23)S102
(24)S101
(25)S103
(26)S100
(27)S120
Figure 10:

Engine Chassis Harness - 2 of 2 (LLY)


Object Number: 1807012  Size: LF
(1)Fuse Block - Underhood (Primary)
(2)S110
(3)C119
(4)C175
(5)C118
(6)S105
(7)S106
Figure 11:

Engine Harness (LLY)


Object Number: 1808808  Size: LF
(1)C134
(2)C133
(3)C119
(4)C118
(5)C113
Figure 12:

Right Side of Engine (LF6)


Object Number: 1877859  Size: LF
(1)C105
(2)Fuse Block - Primary
(3)C102
(4)C121
(5)C109
(6)C101
(7)C100
Figure 13:

Left Side of Engine (LF6)


Object Number: 1877848  Size: LF
(1)C120
(2)Engine Control Module (ECM) C1
(3)Transmission (MWE)
(4)C137
(5)C115
Figure 14:

Engine Splices (LF6)


Object Number: 1877984  Size: LF
(1)S115
(2)S114
(3)S110
(4)S129
(5)S102
(6)S108
(7)S109
(8)S116
(9)S333
(10)S101
(11)S118
(12)S110
(13)S151
(14)S152
(15)S153
(16)S154
Figure 15:

Right Rear Side of Engine Compartment (LF8)


Object Number: 1877844  Size: LF
(1)C109
(2)Fuse Block - Primary
(3)C121
(4)C127
(5)C101
(6)C100
Figure 16:

Front Right Side of Engine Compartment (LF8)


Object Number: 1877841  Size: LF
(1)Engine - LF8
(2)C105
(3)Glow Plug Relay
(4)C111
(5)C125
(6)C102
(7)Transmission Control Module (TCM)
(8)Engine Control Module (ECM)
Figure 17:

Left Side of Engine (LF8)


Object Number: 1877494  Size: LF
(1)C122
(2)Manifold Absolute Pressure (MAP) Sensor
(3)C123
(4)Engine Control Module (ECM) C2
(5)Intake Manifold Temperature (IMT) Sensor
(6)Fuel Temperature Sensor
(7)Suction Control Valve (SCV)
(8)Crankshaft Position (CKP) Sensor
(9)G100
(10)Oil Level Switch
(11)C111
(12)Fuel Rail Pressure (FRP) Sensor
(13)Water in Fuel Sensor
(14)Glow Plug Control Module
(15)Exhaust Gas Recirculation (EGR) Valve
Figure 18:

Front of Engine (LF8)


Object Number: 1877652  Size: LF
(1)Exhaust Gas Recirculation (EGR) Cooler Temperature Sensor 1
(2)Throttle Body
(3)C129
(4)Exhaust Gas Recirculation (EGR) Cooler Temperature Sensor 2
(5)Engine Coolant Temperature (ECT) Sensor
Figure 19:

Front of Engine Compartment (LF8)


Object Number: 1877839  Size: LF
(1)S101
(2)S118
(3)S171
(4)S110
(5)S159
(6)S102
(7)S161
(8)S162
(9)S233
(10)S100, S152
(11)S151
(12)S195
(13)S121
(14)S115
(15)S104
(16)C175
(17)C103
(18)S193
(19)S163
(20)S114
Figure 20:

Body/Roof Harness Routing - w/o Crew Cab


Object Number: 1593956  Size: LF
(1)Cab Panel
(2)C203 (16 cavities) I/P Harness to Body/Roof Harness
(3)S324
(4)Floor Panel
(5)C315 (2 cavities) Console Harness to Body/Roof Harness
Figure 21:

Body/Roof Harness Routing - Crew Cab


Object Number: 1593955  Size: LF
(1)C301 (12 cavities) Body/Roof Harness to Rear Door Harness - Left
(2)S302
(3)S325
(4)S326
(5)C203 I/P Harness to Body/Roof Harness
(6)S324
(7)S312
(8)S310
(9)S308
(10)S322
(11)S335
(12)C302 (12 cavities) Body/Roof Harness to Rear Door Harness - Right
(13)Floor Panel
(14)Blower Motor Relay - Auxiliary (C36)
Figure 22:

I/P Harness 1 of 3


Object Number: 1559694  Size: LF
(1)S261
(2)S232
(3)S264
(4)S259
(5)S217
(6)S204
(7)S252
(8)S223
(9)S202
(10)S412
(11)S220
(12)S203
(13)S222
(14)S253
(15)S230
(16)C206 (4 cavities) I/P Harness to the Body/Roof Harness
(17)G101
(18)Park Brake Switch Connector (C4/C5 and JE3) or C210 (2 cavities) I/P Harness to the Park Brake Harness (C6/C7/C8 and JE3)
(19)C203 (16 cavities) I/P Harness to Body/Roof Harness
(20)S240
Figure 23:

I/P Harness 2 of 3


Object Number: 1559700  Size: LF
(1)SP203 (12 cavities)
(2)C209 (3 cavities - Crew Cab) Body/Roof Harness to the I/P Harness
(3)S249
(4)S219
(5)S211
(6)S222
(7)S213
(8)S200
(9)S212
(10)S273
(11)S274
(12)S214
(13)S255
(14)S245
(15)C202 (30 cavities) I/P Switchbank Harness to the I/P Harness
(16)S210
(17)Data Link Connector (DLC)
(18)S216
(19)C201 (48 cavities) Steering Column Harness to the I/P Harness
(20)S207
Figure 24:

I/P Harness 3 of 3


Object Number: 1559702  Size: LF
(1)Fuse Block-Underhood (Secondary)
(2)C207 (30 cavities) I/P Harness to Cross Body Harness
(3)C109 (40 cavities - L18/LG4/LG5) Engine Chassis Harness to the I/P Harness
(4)C101 (30 cavities) I/P Harness to the Engine Chassis Harness
(5)S269
(6)S218
(7)S260
(8)Junction Block - Underhood Ring Terminal
Figure 25:

I/P Switchbank Harness


Object Number: 1559703  Size: LF
(1)S251
(2)S236
(3)S285
(4)S239
(5)S900
(6)S258
(7)C202 (30 cavities) I/P Switchbank Harness to the I/P Harness
(8)S235
Figure 26:

Cross Body Harness - Left


Object Number: 1559143  Size: LF
(1)C208 (6 cavities) Cross Body Harness to the Stop Lamp Switch Harness
(2)Clutch Pedal Position (CPP) Switch
(3)C211 (22 cavities) Door Harness - Driver to the Cross Body Harness
(4)Cross Body Harness
Figure 27:

Cross Body Harness - Right


Object Number: 1559155  Size: LF
(1)S219
(2)S300
(3)S506
(4)S500
(5)C212 (22 cavities) Door Harness - Passenger to the Cross Body Harness
(6)G103
(7)C207 (30 cavities) I/P Harness to the Cross Body Harness
Figure 28:

Console Harness


Object Number: 1559802  Size: LF
(1)Console
(2)C315 (2 cavities) Console Harness to the Body/Roof Harness
Figure 29:

Park Brake Harness - C6/C7/C8 and JE3


Object Number: 1559807  Size: LF
(1)C210 (2 cavities) I/P Harness to the Park Brake Harness
(2)Park Brake Assembly
(3)Floor Panel
Figure 30:

Door Harness - Driver 1 of 2


Object Number: 1559020  Size: LF
(1)Window Motor - Driver (A31)
(2)C211 (22 cavities) Door Harness - Driver to the Cross Body Harness
(3)C215 (8 cavities) Door Harness - Driver to the Mirror Harness
(4)C217 (8 cavities) Door Harness - Driver to the Cross Body Harness
(5)Door Latch Assembly - Driver Connector C2 (4 cavities - AU3)
(6)Door Latch Assembly - Driver (2 cavities - w/o AU3) or Door Latch Assembly - Driver Connector C1 (2 cavities - AU3)
Figure 31:

Door Harness - Driver 2 of 2


Object Number: 1559022  Size: LF
(1)S503
(2)S504
(3)S505
(4)S500
(5)S502
(6)S501
(7)Door Lock Switch - Driver (AU3) and Window Switch - Driver (A31/Crew Cab)
(8)Speaker - LF Tweeter (ZQ2)
(9)Outside Rearview Mirror Switch (DB6)
Figure 32:

Door Harness - Passenger 1 of 2


Object Number: 1559015  Size: LF
(1)Door Latch Assembly - Passenger (2 cavities - w/o AU3) or Door Latch Assembly - Passenger Connector C1 (2 cavities - AU3)
(2)Door Latch Assembly - Passenger Connector C2 (4 cavities - AU3)
(3)C216 (8 cavities) Door Harness - Passenger to the Mirror Harness
(4)C212 (22 cavities) Door Harness - Passenger to the Cross Body Harness
(5)Window Motor - Passenger (A31)
Figure 33:

Door Harness - Passenger 2 of 2


Object Number: 1559018  Size: LF
(1)S608
(2)S604
(3)S603
(4)S604
(5)S602
(6)Door Lock Switch - Passenger (AU3) and Window Switch - Passenger (A31/Crew Cab)
(7)Speaker - RF Tweeter (ZQ2)
Figure 34:

Chassis Harness Middle Right Frame Rail - Crew Cab Shown, Others Similar


Object Number: 1818384  Size: LF
(1)S431
(2)S430
(3)C409
(4)S319
(5)Splice Pack SP400
(6)S402
(7)C305 - Upfitter Lighting Connector
Figure 35:

Chassis Harness Right Rear Frame Rail


Object Number: 1558182  Size: LF
(1)C412 (8 cavities) Tail Lamp Harness to the Chassis Harness (w/o UZF) or C413 (8 cavities) Tail Lamp Harness to the Backup Alarm Harness (UZF)
(2)Wheel Speed Sensor (WSS) Connector - RR
(3)C409 (8 cavities) Fuel Tank Harness to the Chassis Harness
Figure 36:

Chassis Harness, Rear of Vehicle (JE4)


Object Number: 1861730  Size: LF
(1)Chassis Harness
(2)C406
(3)C401
(4)ABS Harness
Figure 37:

Air Compressor (K16), Fuel Tanks and Trailer Connector (RQ2 and U86 or RQ3)


Object Number: 1014827  Size: LF
(1)Splice Pack SP400 (Ground Block)
(2)C409 (8 cavities) Fuel Tank Harness to the Chassis Harness
(3)Fuel Pump (FP) Relay
(4)Fuel Sender - Secondary
(5)Fuel Tank Transfer Pump - Secondary
(6)Trailer Connector (RQ2 and U86 or RQ3)
(7)C410 (3 cavities - K16) Chassis Harness to the Air Compressor Harness
(8)Air Compressor Connector (K16)
(9)Air Compressor Relay (K16)
(10)Air Compressor (K16)
(11)Fuel Sender - Primary
Figure 38:

Fuel Tank Harness Routing (L18/NK1)


Object Number: 1594015  Size: LF
(1)RH Frame Rail
(2)C409 (8 cavities) Fuel Tank Harness to the Chassis Harness
(3)G408
(4)C406 (4 cavities - HPZ/HR1/HR2) Chassis Harness to the Rear Axle Harness
(5)Fuel Tank
Figure 39:

Fuel Sender Harness


Object Number: 1559707  Size: LF
(1)S418
(2)S407
(3)C420 Fuel Sender Harness to Chassis Harness
(4)S420
(5)G400
(6)Fuel Tank - Secondary
(7)S408
(8)Fuel Tank - Primary
Figure 40:

Tail Lamp Harness and Backup Alarm Harness - UZF


Object Number: 953510  Size: LF
(1)Backup Alarm (UZF)
(2)S410
(3)C412 (8 cavities w/o UZF) Tail Lamp Harness to the Rear Chassis Harness or C413 (8 cavities UZF) Tail Lamp Harness to the Backup Alarm Harness
(4)Tail Lamp Assembly - Right
(5)S411
(6)Tail Lamp Assembly - Left