my Toyota RAV4 XA50 (2019-2024) headlights flicker when idling what's wrong

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, torque wrench, electrical contact cleaner.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Battery Inspection

• Sub-step 1: Remove the battery terminals (negative first, then positive).
• Sub-step 2: Clean the terminals and battery post with a wire brush and electrical contact cleaner.
• Sub-step 3: Reconnect the terminals, ensuring a tight fit.

3. Alternator Testing

• Sub-step 1: Reconnect the battery.
• Sub-step 2: Start the engine and let it idle.
• Sub-step 3: Use a multimeter to measure the voltage at the battery terminals; it should read between 13.7 to 14.7 volts.
• Sub-step 4: If the voltage is low, check the alternator belt for proper tension and wear. Replace if necessary.

4. Wiring Inspection

• Sub-step 1: Visually inspect all wiring leading to the headlights for fraying or damage.
• Sub-step 2: Use a multimeter to check for continuity in the headlight circuit.
• Sub-step 3: Repair or replace any damaged wiring as needed.

5. Relay and Fuse Check

• Sub-step 1: Locate the headlight relay in the fuse box and remove it.
• Sub-step 2: Check the relay for proper operation by testing with a multimeter.
• Sub-step 3: Replace any faulty fuses related to the headlight circuit.