GM Service Manual Online
For 1990-2009 cars
Makes 🢒 Chevrolet 🢒 2004 🢒 C-Series Medium Duty Truck C6/7/8 - Mexico 🢒 Body 🢒 Wiring Systems 🢒 Harness Routing Views
Figure 1:

Front Crossmember, Top View
Object Number: 689483 Size: SF
(1)C101
(2)Horns
Figure 2:

Engine Harness to Starter, Right Side Front View
Object Number: 689486 Size: SF
(1)Engine Harness
(2)C106a/C106b
(3)Starter Temperature Switch, HD Starter with Overcrank Protection
(4)Starter
Figure 3:

Engine Harness to Engine (LG5), Front View
Object Number: 689488 Size: MF
(1)Engine Coolant Temperature (ECT) Gage Sensor
(2)C115
(3)Intake Air (IA) Heater Relay Connector
Figure 4:

Engine (LG5) Harness Components, Left Front View
Object Number: 689490 Size: MF
(1)Upfitter TO PTO Connector
(2)C200
(3)Powertrain Control Module (PCM) Connector
(4)Engine Oil Pressure (EOP) Switch
(5)Engine Oil Pressure (EOP) Gage Sensor
(6)Fuel Heater
Figure 5:

Engine Harness to Engine (LG5), Left Side
Object Number: 689494 Size: MF
(1)C408/C409
(2)Upfitter TO PTO Connector
(3)Upfitter TRANS OPT Connector
(4)Powertrain Control Module (PCM) Connector
(5)Engine Oil Pressure (EOP) Switch
(6)Engine Oil Pressure (EOP) Gage Sensor
(7)Fuel Heater
Figure 6:

Automatic Transmission Harness --Typical-- without MTW/MX4/MWF
Object Number: 689497 Size: MF
(1)To Backup Lamp Switch
(2)Vehicle Speed Sensor (VSS)
(3)Automatic Transmission Modulator
(4)Neutral Safety Switch
(5)C408/C409
Figure 7:

Instrument Panel Harness to IP Mounted Components, Right Front View
Object Number: 689502 Size: MF
(1)Power Brake (P/B) Booster Pump Motor Relay
(2)Park Brake Pump Motor Relay
(3)Trailer Stop Lamp Relay
(4)Transmission Control Relay - MTW/MX4/Ignition Relay -- Engine Controls - L18
(5)ABS Relay Center
(6)Fuse Block 2 -- Underhood
(7)Fuse Block 1 -- Underhood
(8)C123
(9)C121
(10)Windshield Washer Fluid Pump
(11)Windshield Washer Reservoir
Figure 8:

Instrument Panel Harness to Power Brake Booster
Object Number: 689817 Size: SF
(1)G108
(2)C119
(3)Power Brake (P/B) Booster Pump Motor
(4)Power Brake (P/B) Booster Fluid Flow Switch
(5)Brake Fluid Level Switch
Figure 9:

Instrument Panel Harness to Instrument Panel, Left Front
Object Number: 689504 Size: MF
(1)Windshield Wiper Motor
(2)Upfitter AUX WRG Connector, Exterior
(3)Trailer Stop Lamp Switch
(4)C107
(5)C113
(6)Differential Lock Switch
Figure 10:

Exterior Bulkhead, Lower Left Side View
Object Number: 689506 Size: SF
(1)C113
Figure 11:

Exterior Bulkhead, Left Side
Object Number: 689508 Size: SF
(1)C125
(2)P100
(3)C200
Figure 12:

IP Harness to Instrument Panel in Cab, Left Side
Object Number: 689510 Size: SF
(1)C202
(2)To Multifunction Alarm Module
(3)C206
(4)C201
(5)C205
(6)C200
(7)P100
(8)Air Pressure Lines to Gage (JE5)
Figure 13:

IP Harness to Components, Right View
Object Number: 689511 Size: MF
(1)Stop Lamp Switch Interface Module
(2)Convenience Center
(3)SERVICE TRANS FILTER Indicator Lamp
(4)Seat Belt Indicator Lamp
(5)Upfitter Accessory Feed Connector
(6)C210
(7)Upfitter AUX WRG Connector, Interior
(8)Daytime Running Lamps (DRL) Diode
(9)Blower Motor C1
(10)Blower Motor C2
(11)C208
(12)G210
(13)Speaker - RF
Figure 14:

IP Harness to Blower Motor, Left Forward View
Object Number: 689513 Size: MF
(1)Blower Motor Resistor Assembly
(2)Blower Motor C2
(3)Blower Motor C1
(4)C220
(5)Instrument Panel
Figure 15:

HVAC System
Object Number: 689517 Size: LF
(1)Air Temperature Actuator
(2)Recirculation Actuator
(3)Mode Actuator
(4)HVAC Control Module
(5)C204
Figure 16:

Lower IP Components
Object Number: 689521 Size: MF
(1)C215
(2)Ashtray Lamp
(3)Auxiliary Power Posts
(4)Cigar Lighter
Figure 17:

Power Window/Door Lock Harness
Object Number: 689522 Size: SF
(1)C218
(2)C222
(3)C219
(4)P500
(5)C221
(6)C202
Figure 18:

Cab Exterior, Upper Left Front View
Object Number: 689523 Size: MF
(1)Marker Lamps -- Roof
(2)Clearance Lamps
(3)C229
Figure 19:

Cab Interior, Lower Left Side
Object Number: 689524 Size: MF
(1)G211
(2)C223
(3)Park Brake Pressure Indicator Switch
Figure 20:

Battery Cable Routing-Typical
Object Number: 689526 Size: MF
(1)Rear Chassis Harness
(2)C403/C405
(3)Engine Harness
(4)Right Frame Rail
(5)G400
(6)Battery Box
(7)Positive Battery Cable
(8)Negative Battery Cable
(9)Ground Block (G401-G406)
Figure 21:

Fuel Tank(s)
Object Number: 689528 Size: MF
(1)Fuel Pump Harness
(2)Fuel Pump and Sender Assembly -- Left
(3)Fuel Tank -- Left
(4)Fuel Sender and Balance Pump Control Module
(5)Fuel Sender and Balance Pump Control Relay
(6)C411
(7)Fuel Pump and Sender Assembly -- Right