why is my Volkswagen Golf MK7 (2015-2019) alternator draining my battery

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, wrench set.
• Disconnect the negative battery terminal to ensure safety while working on electrical components.

2. Alternator Inspection

• Sub-steps:
  1. Remove the alternator belt using a socket and ratchet to relieve tension on the belt tensioner.
  2. Disconnect the electrical connectors from the alternator carefully.
  3. Unbolt the alternator from its mounting bracket using the appropriate socket size and remove it from the engine compartment.

3. Alternator Testing

• Sub-steps:
  1. Use a multimeter to test the alternator's diodes and voltage output. If the output is below 13.8 volts or the diodes are faulty, replace the alternator.
  2. Inspect the bearings and internal components for wear or damage.

4. Replace or Repair

• Sub-steps:
  1. If the alternator is faulty, install a new or remanufactured alternator by reversing the removal steps.
  2. Reconnect all electrical connectors securely and ensure the mounting bolts are torqued to the manufacturer's specifications.
  3. Reinstall the alternator belt and tension it properly.

5. Reconnect Battery and Test

• Reconnect the negative battery terminal.
• Start the engine and confirm that the battery warning light is off and the voltage at the battery terminals reads between 13.8 to 14.4 volts.