GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC P42 Commercial Chassis 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Tilt Wheel/Column Component Views
Figure 1:

IP Side of Engine Wiring -- All Engines (P42)
Object Number: 180085 Size: MF
(1)Data Link Connector (DLC)
(2)Headlamps Dimmer Switch
(3)Brake Transmission Shift Interlock (BTSI) Solenoid
(4)Brake Transmission Shift Interlock (BTSI) Relay
(5)Horn Relay
(6)Daytime Running Lamps (DRL) Relay
(7)C210
(8)C211
(9)Torque Converter Clutch (TCC) and Stoplamps Switch
(10)Ignition Switch
(11)C1
(12)C2
(13)C1
(14)C2
(15)Turn Signal Switch Connector
(16)Crank Fuse
Figure 2:

Engine to Dash and Steering Column
Object Number: 186178 Size: MF
(1)Ignition Switch
(2)Steering Column
(3)Brake Transmission Shift Interlock (BTSI) Solenoid
(4)Data Link Connector (DLC)
(5)Hazard Lamps Flasher
(6)P100
(7)Fuel Pump Prime
(8)C100
(9)C207
(10)C200
(11)Windshield Wiper Pulse Control Module
Figure 3:

Engine Wiring Harness to Dash and Steering Column
Object Number: 186174 Size: MF
(1)Turn Signal Switch Connector
(2)Headlamps Dimmer Switch
(3)Data Link Connector (DLC)
(4)Powertrain Control Module (Diesel)
(5)Ignition Switch
(6)Brake Transmission Shift Interlock (BTSI) Solenoid
(7)Daytime Running Lamps (DRL) Relay
(7)Daytime Running Lamps (DRL) Relay
(8)Horn Relay
(8)Horn Relay
(9)Brake Transmission Shift Interlock (BTSI) Relay
(10)Fan Control Relay