why does my Volkswagen Golf MK7.5 (2020-Present) battery light stay on

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, wrench set, battery terminal cleaner, serpentine belt tool (if necessary).
• Ensure the vehicle is parked on a flat surface and the engine is off.

2. Clean Battery Terminals

• Disconnect the negative terminal first, followed by the positive terminal.
• Use a battery terminal cleaner to remove corrosion from the terminals and connectors.
• Reconnect the positive terminal first, then the negative terminal.

3. Replace the Battery (if necessary)

• If the battery voltage is below 12.4V, consider replacing it.
• Remove the battery hold-down clamp using the appropriate wrench.
• Disconnect the positive terminal, followed by the negative terminal.
• Lift out the old battery and replace it with a new one, ensuring it is the correct type and size.
• Reconnect the terminals in the order: positive first, then negative.

4. Check/Replace the Alternator

• If the alternator is not producing the correct voltage, it may need to be replaced.
• Disconnect the negative terminal of the battery.
• Remove the serpentine belt using a serpentine belt tool by releasing the tensioner.
• Disconnect the electrical connections and mounting bolts from the alternator.
• Install the new alternator by reversing the removal steps and ensuring proper torque specifications for the mounting bolts.

5. Final Checks

• Reconnect the battery and start the engine.
• Check the voltage output at the battery terminals with the engine running to confirm the alternator is working correctly.