2004 Hyundai Sonata ELECTRICAL PROBLEM

Hi aawilliams,

Thank you for the donation.

Symptoms indicates a possible bad ground connection for the rear ligghts in trunk.

Check the ground connections at left rear of luggage compartment under trim panel.

Was any repairs carried out or damages to body parts prior to this occurring?

The taillights and brake lights share a common ground and uses the same bulb with different circuit. If the ground is bad, any power from the brake circuit would not ba able to ground and the current would be drawn to the next ground of the lighting circuit thus causing the two circuits to be combined. Likewise operating the lighting causes the same conditions.

Recheck the brake lights that were replaced. Try unplugging each bulb and retest. There is a possibility the bulb replaced was not seated correctly. Check the bulb seats for crossed installation ( pluggin bulbs with hook type contacts tends to have the seats goout os position causing the problem if not correctly installed.