1990 BMW M3FACTORY OEM SERVICE PROCEDURE

Circuit Protection Devices

/C In-Line Fuse At left side of evaporator housing. Battery Junction Box On right side of firewall, behind cover. See Figure. On-Board Computer Relay Box Above hood release. See Figure. Power Distribution Box In left rear corner of engine compartment. See Figure. Power Windows Circuit Breaker Near gearshift lever. See Figure.

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.