why do my Toyota RAV4 XA50 (2019-2024) headlights dim when I rev the engine

Solution

1. Preparation

• Gather tools including a multimeter, OBD-II scanner, socket set, and cleaning supplies.
• Ensure the vehicle is parked on a flat surface and the engine is off.

2. Check and Clean Battery Terminal Connections

• Sub-steps:
  1. Disconnect the negative (-) battery terminal first, followed by the positive (+) terminal.
  2. Clean the terminals and cable ends using a wire brush and baking soda solution to remove corrosion.
  3. Reconnect the positive terminal first, followed by the negative terminal.
• Tools Required: Wire brush, cleaning cloth.

3. Inspect and Test the Alternator

• Sub-steps:
  1. Locate the alternator and inspect the wiring for any signs of wear or damage.
  2. Using a multimeter, measure the voltage at the alternator output terminal with the engine running.
  3. If the voltage is below 13.5 volts, replace the alternator.
• Tools Required: Multimeter, socket set.

4. Replace Battery if Necessary

• Sub-steps:
  1. If battery voltage is consistently low, disconnect the battery as previously described.
  2. Remove the old battery and replace it with a new one, ensuring it matches the specifications for your RAV4.
  3. Reconnect terminals and ensure they are tight.
• Parts Required: New battery (if necessary).