GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC P42 Commercial Chassis 🢒 Brakes 🢒 Antilock Brake System 🢒 Hydraulic Brake Component Views
Figure 1:

P/B Booster Warning System Wiring (School Bus) Engine View (Typical)
Object Number: 187806 Size: MF
(1)P102
(2)Power Brake Booster Fluid Flow Indicator/Alarm Switch
(3)Power Brake Booster Pump Pressure Switch
Figure 2:

Radiator Support Wiring (L65)
Object Number: 186179 Size: MF
(1)C203
(2)Torque Converter Clutch (TCC) and Stoplamps Switch
(3)Vehicle Speed Sensor (VSS) Calibrator
(4)Accelerator Pedal Position Module (APP) (Part of Accelerator Pedal Assembly)
(5)Engine Coolant Level Switch
(6)Auxiliary Engine Coolant Fan A/C Pressure Switch
(7)Starter Relay
(8)Brake Pressure Differential Switch
(9)A/C Compressor Relay
(10)Fuel Pump Relay
(11)Park/Neutral Position (PNP) Switch Relay
(12)Stoplamps Switch
Figure 3:

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