why does my BMW 3 Series G20/G21 (2019-2024) smell like burning plastic

Solution

1. Preparation

• Tools Required: Basic hand tools, OBD-II scanner, multimeter, flashlight
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect Wiring Harness

• Sub-steps:
  1. Visual inspection of the wiring harness under the dashboard and engine bay.
  2. Look for any signs of melting or burnt insulation.
  3. Repair or replace any damaged wiring as necessary; use heat-shrink tubing for insulation.

3. Check Electrical Components

• Sub-steps:
  1. Test all electrical components using a multimeter.
  2. Replace any malfunctioning components (e.g., relays, switches).
  3. Ensure all connections are secure and free from corrosion.

4. Verify Fuse Box

• Sub-steps:
  1. Remove the fuse box cover and inspect for blown fuses.
  2. Replace any blown fuses with the correct amperage rating.
  3. Check for signs of melting or damage to the fuse box itself.

5. Inspect Cabin Air Filter and Blower Motor

• Sub-steps:
  1. Remove the cabin air filter and check for debris or blockages.
  2. Inspect the blower motor for any signs of overheating or damage.
  3. Replace the cabin air filter if it is clogged, and consider replacing the blower motor if it is faulty.