GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 HVAC 🢒 HVAC Systems - 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:

A/C Harness
Object Number: 1274242 Size: LF
(1)A/C High Pressure Switch Connector
(2)A/C Compressor Clutch Connector
(3)C102
(4)A/C Low Pressure Switch Connector
(5)S147
(6)A/C Compressor Clutch Relay
(7)Diode
(8)S148
Figure 3:

Right Front of Vehicle
Object Number: 826872 Size: LF
(1)Exhaust Brake Actuator Control Solenoid Valve (K40/NPE)
(2)Exhaust Brake Actuator Control Solenoid Valve Connector (K40/NPE)
(3)C121 (10 cavities - Upfitter PTO Connector)
(4)Exhaust Brake Relay (K40/NPE)
(5)G100
(6)C104 (6 cavities - LG4/LG5/LLY) Engine Chassis Harness to the Exhaust Brake Harness
(7)Battery Isolator (VNF)
(8)C101 (30 cavities) I/P Harness to the Engine Chassis Harness
(9)C124 (24 cavities) I/P Harness to the Engine Chassis Harness
(10)Exhaust Brake Harness
(11)Engine Chassis Harness
Figure 4:

Backup Alarm Siren, C412, Tail Lamp - Left, Right
Object Number: 953510 Size: LF
(1)Backup Alarm (UZF)
(2)S410
(3)C412
(4)Tail Lamp Assembly - Right
(5)S411
(6)Tail Lamp Assembly - Left
Figure 5:

Back Right of the Engine Compartment
Object Number: 822087 Size: LF
(1)Powertrain Control Module (PCM) Connector
(2)Powertrain Control Module (PCM)
(3)Throttle Actuator Control (TAC) Module
(4)I/P Harness
(5)Throttle Actuator Control (TAC) Module - C1
(6)Throttle Actuator Control (TAC) Module - C2
(7)Engine Harness
Figure 6:

Body Harness
Object Number: 1274590 Size: LF
(1)Marker Lamp - Roof
(2)Marker Lamp - Roof
(3)Marker Lamp - Roof
(4)Marker Lamp - Roof
(5)Marker Lamp - Roof
(6)Marker Lamp - Roof
(7)Dome/Reading Lamp - Front
(8)Dome/Reading Lamp - Rear
(9)Rear Window Defogger Grid Connector
(10)S301
(11)S302
(12)S325
(13)C700
(14)Blower Motor - Auxiliary C1
(15)Blower Motor - Auxiliary C2
(16)Blower Motor Resistor - Auxiliary
(17)Blower Motor Relay - Auxiliary
(18)Coolant Bypass Valve Solenoid
(19)S323
(20)S324
(21)C315
(22)C800
(23)Inflatable Restraint Sensing and Diagnostic Module (SDM)
(24)S338
(25)S337
(26)S336
(27)S308
(28)S310
(29)S500
(30)S330
(31)C206
(32)C203
(33)Inflatable Restraint Diagnostic Resistor
(34)C209
(35)C204
Figure 7:

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 8:

Chassis Harness - 1 of 3
Object Number: 1274766 Size: LF
(1)S320
(2)C108
(3)S321
(4)C107
(5)S900
(6)S901
(7)Wheel Speed Sensor (WSS) - RF
(8)C214
(9)C100
(10)C405
(11)Electronic Air Compressor
(12)S404
(13)S400
(14)Electronic Brake Control (EBCM) Module
(15)Wheel Speed Sensor (WSS) - LF
(16)C117
(17)Horn
(18)Inflatable Restraint Front End Sensor
(19)S403
Figure 9:

Chassis Harness - 2 of 3
Object Number: 1274774 Size: LF
(1)S409
(2)S257
(3)S256
(4)C305 - Upfitter Lighting Connector (12 cavities - Chassis Harness to Upfitter Harness)
(5)Splice Pack SP400 (Ground Block)
Figure 10:

Chassis Harness - 3 of 3
Object Number: 1274782 Size: LF
(1)C409
(2)C412
(3)Wheel Speed Sensor (WSS) - RR
Figure 11:

Console Harness
Object Number: 1274608 Size: LF
(1)C315
(2)Cigar Lighter
Figure 12:

Crossbody Harness - 1 of 2
Object Number: 1274659 Size: LF
(1)S219
(2)S300
(3)S506
(4)S500
(5)C600
(6)G103
(7)C207
Figure 13:

Cross Body/Brake Harness - 2 of 2
Object Number: 1274669 Size: LF
(1)Clutch Pedal Position (CPP) Switch
(2)Stop Lamp Switch Connector
(3)C208
(4)C500
Figure 14:

Driver Door Harness - 1 of 2
Object Number: 1274733 Size: LF
(1)C500
(2)S503
(3)S502
(4)Mirror Control Switch
(5)Window Switch - Driver C1 (Crew Cab Only)
(6)Window Switch - Driver (Regular Cab) C2 (Crew Cab Only)
(7)S501
(8)Window Motor - Driver
(9)S500
(10)Door Lock Switch - Passenger
(11)Speaker - RF Tweeter
(12)Speaker - RF Door
(13)S504
(14)S505
(15)Outside Rearveiw Mirror (OSRVM) - Driver
(16)C206
Figure 15:

Driver Door Harness - 2 of 2
Object Number: 1274751 Size: LF
(1)Door Jamb Switch
(2)Door Lock Actuator - Passenger
Figure 16:

Engine Chassis Harness - 1 of 2 (LLY)
Object Number: 1806988 Size: LF
(1)S120
(2)S275
(3)S276
(4)S118
(5)S100
(6)C105
(7)G100
(8)C175
(9)C100
(10)S166
(11)C124
(12)C102
(13)C101
(14)S107
(15)S164
(16)S121
(17)S102
(18)S173
(19)S101
(20)C121
(21)S103
Figure 17:

Engine Harness (LLY)
Object Number: 1808067 Size: LF
(1)C119
(2)C118
(3)C113
Figure 18:

Engine Harness (LLY)
Object Number: 1808067 Size: LF
(1)C119
(2)C118
(3)C113
Figure 19:

Engine Exhaust Brake Harness
Object Number: 1274752 Size: LF
(1)Exhaust Brake Relay
(2)C104
(3)S303
(4)Exhaust Brake Solenoid
Figure 20:

Engine Harness 6.6L - 1 of 2
Object Number: 1274884 Size: LF
(1)S106
(2)Glow Plug
(3)Secondary Generator
(4)Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor
(5)Glow Plug
(6)Generator
(7)C102
(8)Engine Control Module (ECM) Connector C1
(9)Fuse Block-Underhood (Primary)
(10)Engine Control Module (ECM) Connector C2
(11)S276
(12)S275
(13)S120
(14)S118
(15)C121 (10 cavities - Upfitter PTO Connector)
(16)S103
(17)S101
(18)S100
(19)S146
(20)S121
(21)S102
(22)C101 (30 cavities) I/P Harness to the Engine Chassis Harness
(23)C124 (24 cavities) I/P Harness to the Engine Chassis Harness
(24)C102 (Upfitter PTO Connector - 10 cavities - PTO)
(25)C100 (30 cavities) Chassis Harness to the Engine Chassis Harness
(26)Transmission Control Module (TCM) Connector C1
(27)Transmission Control Module (TCM) Connector C2
(28)G202
(29)C119 (24 cavities) Engine Harness to the Engine Chassis Harness
(30)C118 (40 cavities) Engine Harness to the Engine Chassis Harness
(31)Glow Plug
Figure 21:

Engine Harness 6.6L - 2 of 2
Object Number: 1274886 Size: LF
(1)Park/Neutral Position (PNP) Switch Connector C1 (Allison® LCT)
(2)Turbine Shaft Speed (TSS) Sensor (Allison® LCT)
(3)Automatic Transmission Input Shaft Speed (AT ISS) Sensor (Allison® LCT)
(4)Vehicle Speed Sensor (VSS)
(5)C111
(6)Junction Block - Underhood
(7)C175 (20 cavities - Allison® LCT) Engine Harness to the Internal Transmission Harness
(8)Park/Neutral Position (PNP) Switch Connector C2 (Allison® LCT)
Figure 22:

Fuel Sender
Object Number: 1274648 Size: LF
(1 )Fuel Sender
(2)S420
(3)Fuel Pump Relay - Secondary
(4)Wheel Speed Sensor (WSS) - LR (JE3/C4/C5/C6/C7)
(5)S408
(6)S407
(7)S418
(8)G400
(9)Fuel Transfer Pump - Secondary
(10)Fuel Sender - Secondary
(11)C420
Figure 23:

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 24:

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 25:

I/P Harness - 1 of 2
Object Number: 1274656 Size: LF
(1)S223
(2)S202
(3)S279
(4)S200
(5)S280
(6)S212
(7)S203
(8)S220
(9)S412
(10)S273
(11)S274
(12)S214
(13)Inflatable Restraint I/P Module
(14)Air Temperature Actuator
(15)S209
(16)Blower Motor Relay
(17)Fuse Block - Underhood (Secondary)
(18)G202
(19)C109
(20)S218
(21)S260
(22)C101
(23)S269
(24)C207
(25)G103
(26)S232
(27)C201
(28)S206
(29)S268
(30)S284
(31)S207
(32)S244
(33)S255
(34)S245
(35)Aux Power 1
(36)S243
(37)S265
(38)Aux Power 2
(39)C202
(40)S205
Figure 26:

I/P Harness - 2 of 2
Object Number: 1274657 Size: LF
(1)S249
(2)Headlamp Switch
(3)S261
(4)S232
(5)S264
(6)S259
(7)S217
(8)Instrument Panel Cluster (IPC)
(9)Windshield Wiper Motor
(10)S252
(11)Turn Signal/Hazard Flasher Module
(12)S253
(13)Transfer Case Shift Control Switch
(14)Daytime Running Lamps (DRL) Diode
(15)Overdrive Defeat Switch
(16)S210
(17)S213
(18)Radio
(19)S222
(20)Driver Information Center (DIC)
(21)HVAC Control Assembly - C2
(22)HVAC Control Assembly - C1
(23)S211
(24)S216
(25)S219
(26)Data Link Connector (DLC)
(27)J1939 Terminator
(28)Diagnostic Tool Connector
(29)Serial Data Gateway
(30)Chime Module
(31)Accelerator Pedal Position (APP) Sensor
(32)S230
(33)S204
(34)C201
(35)Inflatable Restraint Steering Wheel Module
(36)S207
(37)C209
(38)HVAC Control Assembly - C3
(39)C210 (JE3) or C304 (RQ2 and U86 or RQ3)
(40)C206
(41)Park Brake Foot Switch
(42)G101
(43)C203
(44)Windshield Washer Fluid Pump
(45)S240
(46)Splice Pack SP203
(47)Daytime Running Lamps (DRL) Diode
Figure 27:

Lower Right Side of the Engine
Object Number: 1217665 Size: MF
(1)G118
(2)Engine Block
(3)G120
(4)G119
Figure 28:

Park Brake Harness
Object Number: 1274646 Size: LF
(1)C210
(2)Park Brake Switch Connector
Figure 29:

Passenger Door Harness-1 of 2
Object Number: 1274754 Size: LF
(1)C500
(2)S603
(3)S244
(4)Mirror Control Switch
(5)Window Switch - Passenger
(6)S208
(7)Door Lock Switch - Passenger
(8)Speaker - RF Tweeter
(9)Speaker - RF Door
(10)Window Motor - Passenger
(11)S602
(12)S604
(13)Outside Rearview Mirror - Passenger
Figure 30:

Passenger Door Harness-2 of 2
Object Number: 1274760 Size: LF
(1)Door Jamb Switch - Passenger
(2)Door Lock Actuator - Passenger
Figure 31:

Rear Lamp Harness
Object Number: 1274615 Size: LF
(1)C412
(2)S410
(3)S411
(4)Right Hand Tail Lamp Connector
(5)Left Hand Tail Lamp Connector