1986 GMC S15 Service and Repair Manual

1986 GMC S15 service and repair manual — a detailed, factory-style reference for maintenance, diagnostics, and repair. Use it to confirm correct procedures, specifications, and system coverage before you start work.

Designed for technicians and DIY owners, this manual helps you troubleshoot accurately, follow step-by-step repair procedures, and reference wiring diagrams and system sections quickly while you work.

What’s included

• Step-by-step repair procedures and service information
• Specifications and reference data (where provided)
• Wiring diagrams and electrical sections
• Powertrain, brakes, steering, suspension, HVAC and more

Trims covered

• Base Extended Cab Pickup 2-Door
• Base Standard Cab Pickup 2-Door
• Sierra Classic Extended Cab Pickup 2-Door
• Gypsy Extended Cab Pickup 2-Door
• High Sierra Standard Cab Pickup 2-Door
• Base Cab & Chassis 2-Door
• Gypsy Standard Cab Pickup 2-Door
• High Sierra Extended Cab Pickup 2-Door
• Sierra Classic Standard Cab Pickup 2-Door

Engines covered

• 2.8L 173Cu. In. V6 GAS OHV Naturally Aspirated
• 2.5L 2474CC 151Cu. In. l4 GAS OHV Naturally Aspirated

Index / Table of contents

• Body
• Brakes
• Chassis Electrical
• Driveline
• Engine Cooling
• Engine Electrical
• Engine Mechanical
• Engine Performance & Emission Controls
• Fuel System
• General Information & Identification
• Heating, Ventilation, & Air Conditioning
• Hybrid & Electric Vehicle Systems
• Steering
• Suspension
• Transmission, Clutch, & Transfer Case
• Wiring Diagrams