my Toyota Highlander Fourth Generation (2020-present) battery drains overnight what should I check

Solution

1. Preparation

• Tools Required: Multimeter, ammeter, basic socket set, and screwdriver set.
• Disconnect the negative battery terminal to ensure safety while working on the electrical system.

2. Battery Replacement (if necessary)

• Sub-steps:
  1. Remove the negative terminal first, followed by the positive terminal.
  2. Unfasten the battery hold-down clamp using the appropriate socket size.
  3. Lift the old battery out carefully.
  4. Place the new battery into the tray, ensuring proper orientation.
  5. Reinstall the hold-down clamp and tighten it securely.
  6. Connect the positive terminal first, followed by the negative terminal.

3. Address Parasitic Draw

• Sub-steps:
  1. After confirming that the battery is in good condition, reconnect the negative terminal.
  2. With the ammeter still connected, start removing fuses one at a time to identify the circuit causing the parasitic draw.
  3. Once the draw drops below 50 milliamps, identify the faulty component related to the blown fuse.
  4. Repair or replace the faulty component as necessary.

4. Final Inspection

• Sub-steps:
  1. Ensure all electrical components are functioning properly.
  2. Verify that no lights are left on overnight (interior and exterior).
  3. Test the vehicle by letting it sit overnight and checking for battery voltage in the morning.