This comprehensive troubleshooting manual is specifically designed for the BMW 850i (E31) model, covering vehicles produced between July 1991 and August 1992. It provides detailed information and step-by-step guidance to help diagnose and resolve a wide range of electrical issues that you might encounter. The manual begins with an introduction and essential symbols used throughout. It then presents a detailed power distribution chart, fuse chart, ground distribution diagram, and data link information, laying the foundation for understanding the car's electrical system. Next, it dives into specific electrical system components and their troubleshooting procedures. You will find comprehensive sections dedicated to:

* **Engine Control System:** Covers diagnostics and repair of the engine's electrical components, including sensors, actuators, and the ECU itself.
* **Charging System:** Addresses issues related to the alternator, battery, and charging circuit.
* **Start System:** Provides troubleshooting guidance for the starter motor, ignition system, and related components.
* **Electronic Transmission Control:** Details diagnostics and repair procedures for the transmission's electronic control unit and associated components.
* **Supplement Restraint System (SRS):** Offers guidance on troubleshooting and repairing the airbag system.
* **Slip Control ABS:** Covers diagnostics and repair of the anti-lock braking system and traction control.

Beyond these core systems, the manual also explores various other electrical components and their troubleshooting procedures, including:

* **Power Mirrors:** Details how to diagnose and repair issues with power-adjustable side mirrors.
* **Central Locking Module:** Guides you through troubleshooting and repairing the central locking system.
* **Power Windows:** Provides detailed information on diagnosing and fixing problems with the power windows.
* **Power Seats:** Covers troubleshooting and repair procedures for the power-adjustable seats.
* **Heated Seats:** Details diagnostics and repair of the heated seat system.
* **Power Sunroof:** Offers guidance on troubleshooting and fixing problems with the power sunroof.
* **Horn:** Provides troubleshooting information related to the horn system.
* **Wiper/Washer Module:** Details diagnostics and repair of the windshield wiper and washer system.
* **Headlight Washer:** Covers troubleshooting and repair procedures for the headlight washer system.
* **Windshield Washer Jet Heaters:** Provides guidance on diagnosing and fixing problems with the windshield washer jet heaters.
* **Instrument Cluster:** Covers troubleshooting and repair of the instrument cluster and its gauges.
* **Multi-Function Clock:** Details diagnostics and repair of the multi-function clock display.
* **Light Switch Details:** Provides detailed information on troubleshooting and repairing the light switch.
* **Headlights/Fog Lights:** Covers diagnostics and repair procedures for the headlights and fog lights.
* **Turn/Hazard Lights:** Details troubleshooting and repair of the turn signal and hazard lights.
* **Park/Tail/Underhood Lights:** Provides guidance on diagnosing and fixing problems with the parking lights, taillights, and underhood lights.
* **License Plate/Luggage Compartment Lights:** Covers troubleshooting and repair of the license plate and luggage compartment lights.
* **Back Up Lights:** Details diagnostics and repair of the backup lights.
* **Brake Lights:** Provides guidance on troubleshooting and fixing problems with the brake lights.
* **Interior Lights:** Covers troubleshooting and repair procedures for the interior lighting system.
* **Glove Box Light/Cassette Box/Ashtray Lights/Charging Socket:** Details diagnostics and repair of these lighting and charging components.
* **Crash Control Module:** Offers guidance on troubleshooting and repairing the crash control module.
* **Park/Ventilation with HKR:** Covers diagnostics and repair of the parking/ventilation system.
* **Rear Window Defogger:** Provides guidance on troubleshooting and fixing problems with the rear window defogger.
* **Integrated Climate Regulation:** Details diagnostics and repair of the climate control system.
* **Radio/CD Player:** Covers troubleshooting and repair procedures for the radio and CD player.
* **Radio/HiFi System:** Provides guidance on diagnosing and fixing problems with the audio system.
* **Cellular Telephone:** Details diagnostics and repair of the integrated cellular telephone (if equipped).
* **Cruise Control (Tempomat):** Covers troubleshooting and repair of the cruise control system.
* **Anti-Theft System:** Offers guidance on troubleshooting and repairing the anti-theft system.
* **On-Board Computer:** Provides guidance on diagnosing and fixing problems with the on-board computer system.

The manual concludes with a component location chart, detailed component location views, splice location views, and connector views, which are invaluable for locating specific components and wiring harnesses within the vehicle. This comprehensive troubleshooting manual equips you with the essential knowledge and step-by-step procedures to confidently diagnose and resolve electrical issues on your BMW 850i (E31) from 1991 to 1992.

The BMW 850i (E31) was a grand tourer produced by BMW from 1990 to 1999. The first generation of the 8 Series, the E31, was a highly acclaimed and luxurious car that aimed to compete with the Mercedes-Benz S-Class Coupe and the Ferrari 456. The 850i, launched in 1990, was the base model, equipped with a powerful 5.0-liter V12 engine producing 300 horsepower. It featured a sleek and aerodynamic design, with a low-slung profile and a long, flowing hood. The interior was equally impressive, boasting high-quality materials, ample legroom, and a luxurious atmosphere. The 850i was renowned for its smooth and effortless performance, providing a comfortable and refined driving experience. The car also incorporated advanced technology for its time, including an optional electronic stability control system and a sophisticated airbag system.

However, the E31 8 Series, despite its technological advancements, was also known for its complex electrical systems, which could pose challenges for troubleshooting. This complexity arose from the integration of numerous electronic components and sensors, contributing to the car's advanced features. A dedicated electrical troubleshooting manual for the 1991-1992 model years of the 850i is a valuable resource for technicians and enthusiasts alike. This manual serves as a comprehensive guide to understanding the complex electrical system of the vehicle, providing step-by-step instructions and diagnostic procedures to identify and resolve electrical faults. The manual includes detailed wiring diagrams, component specifications, and troubleshooting charts, allowing users to pinpoint specific problems and provide effective solutions. By utilizing this manual, individuals can confidently address electrical issues, ensuring optimal performance and reliability of their 1991-1992 BMW 850i.