why does my Acura MDX YF3 (2022-Present) headlights flicker when driving

Symptoms

• Flickering or dimming of headlights when driving.
• Possible accompanying symptoms such as dashboard lights flickering.
• Intermittent loss of power to other electrical components (e.g., radio, interior lights).
• Possible warning lights on the dashboard (e.g., battery warning light).

Diagnostic Steps

1. Check for Error Codes

   • Use an OBD-II scanner to check for any diagnostic trouble codes (DTCs) that may indicate electrical issues or component failures.

2. Inspect Battery and Connections

   • Visually inspect the battery for corrosion or loose connections.
   • Use a multimeter to check the battery voltage (should be around 12.6 volts with the engine off and 13.7-14.7 volts with the engine running).

3. Check Alternator Output

   • With the engine running, measure the voltage at the battery terminals using the multimeter.
   • If the voltage is below 13.7 volts, the alternator may be failing.

4. Inspect Headlight Assembly and Wiring

   • Inspect the headlight bulbs for proper seating and condition.
   • Check the wiring harness for any signs of wear, damage, or loose connections.

5. Test Headlight Relay

   • Locate the headlight relay in the fuse box.
   • Swap it with a similar relay (e.g., horn relay) to see if the flickering persists.

Repair Instructions

1. Battery and Connection Repair

   • If corrosion is found, clean the battery terminals and cable connections using a wire brush.
   • Tighten any loose connections.

2. Alternator Replacement (if needed)

   • Disconnect the negative battery terminal.
   • Remove the serpentine belt from the alternator.
   • Disconnect the electrical connectors and mounting bolts from the alternator.
   • Install the new alternator and reconnect everything.
   • Reconnect the negative battery terminal.

3. Headlight Bulb Replacement

   • Open the hood and locate the headlight assembly.
   • Remove the headlight bulb connector and replace the bulb (ensure not to touch the glass with bare hands).
   • Reinsert the bulb and reconnect the connector.

4. Wiring Repair

   • Repair or replace any damaged wiring found during inspection.
   • Ensure all connections are secure.

5. Headlight Relay Replacement

   • If the relay was defective, replace it with a new relay.
   • Ensure it is seated firmly in the fuse box.

Tools Required

• OBD-II scanner
• Multimeter
• Socket set (including extensions)
• Torque wrench (for alternator bolts)
• Wire brush for battery terminals
• Replacement headlight bulbs (if necessary)
• Replacement parts (if necessary: alternator, relay)

Estimated Time for Repair

• Battery and connections: 30 minutes
• Alternator replacement: 2-3 hours
• Headlight bulb replacement: 15-30 minutes
• Wiring repair: time varies based on extent of damage
• Relay replacement: 15 minutes

Safety Warnings

• Always disconnect the negative battery terminal before working on electrical components to prevent shorts.
• Use gloves and safety glasses when handling electrical components and tools.