This comprehensive repair manual provides detailed instructions for all repairs on your BMW 525i-535i m5 (E34) model from 1990 to 1991. It is the same manual used by professional mechanics, enabling you to save money by performing repairs yourself. The manual offers a wealth of technical information, clear illustrations, diagrams, specifications, and step-by-step explanations, making it easy to understand even with limited automotive knowledge. With this manual, you can confidently service and maintain your car to a factory-spec standard.

The manual covers a wide range of systems and components, including:

* **Electrical System:** Power distribution, fuse chart, ground distribution, data link, charging system, start system, electronic transmission control, supplemental restraint system (SRS), slip control ABS, power mirrors, central locking module, power windows, power seats, heated seats, power sunroof, horn, wiper/washer module, headlight washer, windshield washer jet heaters.
* **Interior:** Instrument cluster, multifunction clock, light switch details, headlights/fog lights, turn/hazard 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, radio/CD player, radio/hifi, cellular telephone, cruise control (Tempomat), anti-theft system, on-board computer.
* **Component Location:** Component location charts, component location views, splice location views, connector views.

The BMW 5 Series (E34) is a mid-size executive car produced by BMW from 1988 to 1995. It was the fourth generation of the 5 Series, succeeding the E28, and was replaced by the E39 in 1995. The E34 was initially launched with a range of petrol and diesel engines, including the inline-six M20 and M50 engines, along with a V8 M60 engine introduced in 1992. The M5, a high-performance variant, featured a naturally aspirated 3.5-liter S38 engine, producing a formidable 315 horsepower. The E34 5 Series was praised for its handling, performance, and luxurious interior. It also introduced significant advancements in safety features, including anti-lock brakes (ABS) and driver airbags.

Focusing on the 1990-1991 models specifically, the 525i and 535i models featured the M20 and M50 engines respectively, while the M5 remained powered by the S38 engine. Electrical troubleshooting for these models can be a complex process due to the sophisticated electrical systems present in these cars. Common electrical issues include faulty sensors, wiring problems, failing actuators, and defective control modules. The E34's electrical architecture encompasses a multitude of components, including the engine control unit (ECU), body control module (BCM), instrument cluster, and numerous sensors and actuators. Each component plays a crucial role in the car's operation, and malfunctioning electrical systems can lead to a range of symptoms, such as engine starting problems, malfunctioning lights, faulty gauges, and malfunctioning power accessories. Diagnosing and troubleshooting these issues often requires specialized tools and knowledge, and access to wiring diagrams and fault codes.