my Toyota Corolla E170 (2013-2019) headlights are flickering what's the cause

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Replace Headlight Bulbs (if faulty)

• Tools Required: Socket set, gloves, safety glasses.
• Sub-steps:
  1. Open the hood and locate the headlight assembly.
  2. Remove the headlight assembly by unscrewing the retaining bolts.
  3. Disconnect the electrical connector from the back of the bulb.
  4. Remove the old bulb by turning it counterclockwise.
  5. Insert the new bulb, ensuring not to touch the glass with bare hands.
  6. Reconnect the electrical connector and reassemble the headlight assembly.

3. Check and Replace Battery (if necessary)

• Tools Required: Multimeter, wrench set.
• Sub-steps:
  1. Using a multimeter, confirm the battery voltage is below 12.4 volts.
  2. If necessary, remove the battery by disconnecting the negative terminal first, followed by the positive terminal.
  3. Remove the battery hold-down clamp and lift the battery out.
  4. Install the new battery in reverse order, ensuring secure connections.

4. Inspect and Replace Alternator (if necessary)

• Tools Required: Multimeter, socket set, torque wrench.
• Sub-steps:
  1. Check the alternator output using the multimeter while the engine is running.
  2. If the voltage is below 13.8 volts, remove the alternator as follows:
     1. Disconnect the negative battery terminal.
     2. Remove the serpentine belt.
     3. Disconnect the electrical connectors from the alternator.
     4. Remove the mounting bolts and lift out the alternator.
  3. Install the new alternator by reversing the removal steps.
  4. Reattach the serpentine belt and reconnect the battery terminals.

5. Repair Wiring and Ground Connections (if corroded)

• Tools Required: Wire brush, electrical tape, connectors.
• Sub-steps:
  1. Locate the ground connections for the headlights and inspect for corrosion.
  2. Clean any corrosion using a wire brush.
  3. Secure connections tightly and use electrical tape to cover any exposed wiring.