This comprehensive repair manual provides detailed instructions for servicing and repairing your BMW 525i-535i (E34) from 1988 to 1989. It covers a wide range of systems, offering step-by-step guidance for even the most novice mechanic. The manual includes detailed illustrations, diagrams, technical specifications, and in-depth explanations for each repair procedure. With this manual, you can confidently tackle repairs and maintenance tasks with the same level of expertise as a professional mechanic.

The manual covers key systems including:

* **Powertrain:** Engine Control System, Charging System, Starting System, Electronic Transmission Control.
* **Safety:** Supplement Restraint System, Slip Control ABS.
* **Comfort & Convenience:** Power Mirrors, Central Locking Module, Power Windows, Power Seats, Heated Seats, Power Sunroof, Horn, Wiperwasher Module, Headlight Washer, Windshield Washer Jet Heaters.
* **Electrical:** Power Distribution, Fuse Chart, Ground Distribution, Data Link.
* **Interior:** Instrument Cluster, Multi Function Clock, Light Switch Details, Headlights/Fog Lights, Turnhazard Lights, Park/Tail/Underhood Lights, License Plate/Luggage Compartment Lights, Back Up Lights, Brake Lights, Interior Lights, Glove Box Light/Cassette Box Ashtray Lights/Charging Socket, Crash Control Module, Park, Ventilation with HKR, Rear Window Defogger, Integrated Climate Regulation.
* **Audio & Communication:** Radio/CD Player, Radio/HiFi, Cellular Telephone.
* **Driver Assistance:** Cruise Control Tempomat, Anti Theft System, On Board Computer.
* **Component Location:** Component Location Chart, Component Location Views, Splice Location Views, Connector Views.

With this manual, you have access to the same technical information used by professional garages and workshops. It's the perfect tool for anyone looking to save money on repair costs and gain a deeper understanding of their vehicle.

The BMW 5 Series (E34) is a mid-size luxury sedan produced by BMW from 1988 to 1995. The E34 generation marked a significant departure from its predecessor, the E28, introducing a new platform and a more modern design language. It was available in a range of engine options, including the 525i and 535i models that are the focus of this document. The 525i was powered by a 2.5-liter inline-six engine, while the 535i featured a larger 3.5-liter inline-six. Both engines were known for their smooth and powerful performance, delivering a compelling driving experience. The E34 5 Series was also known for its refined interior, with high-quality materials and a comfortable ride. It offered features like power windows, power steering, and air conditioning, making it a luxurious option for its time.

The E34 5 Series was a technological marvel for its time, incorporating advanced features like anti-lock brakes (ABS) and a sophisticated suspension system. However, like any complex machine, it was prone to electrical issues. This document focuses on providing detailed troubleshooting information for common electrical problems that may arise in 1988-1989 E34 525i and 535i models. The information contained within covers a wide range of electrical components, including the engine control unit (ECU), sensors, wiring harnesses, and electrical accessories. It is designed to serve as a comprehensive guide for individuals seeking to diagnose and resolve electrical problems on their E34 5 Series. By understanding the fundamental principles of electrical troubleshooting and utilizing the information presented in this document, owners and mechanics can effectively address electrical issues and maintain the reliability of their beloved E34.