my Ford Mustang S650 (2024-Present) has dimming headlights at idle, what's wrong?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is off.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect Battery and Connections

• Remove the battery terminals (negative first, then positive).
• Clean any corrosion from the terminals and cable ends using a wire brush.
• Ensure that the connections are tight and secure upon reinstallation.

3. Test and Replace Battery (if necessary)

• Use a multimeter to measure the battery's voltage; it should read around 12.6 volts when fully charged.
• If the voltage is below 12.4 volts, consider charging or replacing the battery.
• Reinstall the battery terminals, ensuring a tight connection.

4. Alternator Inspection

• Reconnect the negative battery terminal.
• Start the engine and use a multimeter to measure the voltage at the battery terminals; it should read between 13.8 to 14.2 volts.
• If the voltage is below this range, the alternator may need replacement or further inspection.

5. Check Serpentine Belt

• Inspect the serpentine belt for wear, cracks, or damage.
• If the belt is worn, replace it according to manufacturer specifications.
• Ensure the tensioner is functioning properly so that the belt maintains appropriate tension.

6. Reassemble and Final Checks

• Reassemble any components removed during the inspection.
• Ensure all electrical connections are secure.
• Reconnect the battery and perform a final voltage test.