my BMW 3 Series won’t start but the lights are on what’s the issue

Solution

1. Preparation

• Ensure the vehicle is in a safe, well-ventilated area.
• Disconnect the negative battery terminal to prevent electrical shock during repair.

2. Battery Inspection and Replacement

• Sub-steps:
  1. Inspect the battery terminals for corrosion. Clean with a wire brush and a mixture of baking soda and water if necessary.
  2. If the battery voltage is below 12.4 volts, recharge or replace the battery.
  3. Reconnect the battery terminals, ensuring a snug fit.

3. Starter Motor and Relay Inspection

• Sub-steps:
  1. Locate the starter motor and inspect its wiring harness for damage or loose connections.
  2. Remove the starter relay from the fuse box and test it with a multimeter for continuity.
  3. If faulty, replace the starter relay.

4. Ignition Switch Testing

• Sub-steps:
  1. Disconnect the wiring harness from the ignition switch.
  2. Using a multimeter, check for continuity between the terminals when the key is turned to the "start" position.
  3. If no continuity is detected, replace the ignition switch.

5. Starter Motor Replacement (if necessary)

• Sub-steps:
  1. Disconnect the negative battery terminal again.
  2. Remove any covers obstructing access to the starter motor.
  3. Unbolt the starter motor from the transmission and remove it.
  4. Install the new starter motor, ensuring it is secured with the proper torque specifications.
  5. Reconnect the wiring harness and battery terminal.