GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 TopKick C-Series (Conventional) C4/C5 🢒 HVAC 🢒 HVAC - Manual 🢒 Harness Routing Views
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