In the following source in the bottom of the article, the pdf document of 1991 BMW 325i convertible troubleshooting manual and wiring diagrams is presented. Within the schematics, all switches and sensors are shown “at rest” as though the ignition switch were off. For identification, component names are underlined and placed next to or above each component. Notes are included, describing how switches and other components work.
The power distribution schematics shows the current feed through all the connections from the battery and alternator to each fuse and the ignition and light switches. If the power distribution schematic is combined with any other circuit schematic, a complete picture is made of how that circuit works. The Ground Distribution schematics show how several circuits are connected to common grounds. The circuit schematics diagram illustrated inside the manual are those of the power distribution, ground distribution, injection electronics, supplemental restraint systems, power windows, heated seats, electro-mechanical convertible top, instrument cluster, light switch details, headlights/foglights, turn/hazard lights, back up lights, interior lights, a/c compressor controls, radio/antenna,connector views, and the accessory connector.
Get more details about the pdf document from the following source :
1991 BMW 325i CONVERTIBLE ELECTRICAL TROUBLESHOOTING MANUAL AND SCHEMATIC DIAGRAM DOWNLOAD