♔♔♔ The following wiring diagram and harness applies for BMW M3 1988 model year. This manual is primarily designed to show the electrical schematics and wiring diagram of BMW M3 in a manner that makes electrical troubleshooting easier. In this manual, electrical components which work together are shown together on one schematic. At the top of the page, you can find the fuse (positive) that powers the circuit. The flow of current is shown through all wires, connectors, switches, and motors to ground (negative) at the bottom of the page.