One problem related to brake light has been reported for the 2005 Mercury Grand Marquis. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2005 Mercury Grand Marquis based on all problems reported for the 2005 Grand Marquis.
While driving at night, the headlights suddenly go out. This is very dangerous, regardless of either driving on the highway or in the city (especially with pedestrians). They tend to stay out for 10-15 min before they start working again. While they are out, the brake lights go out at the same time, making it even more scarier, cant see to drive, and the car behind me cant see me slowing down or stopping, which increases the chances for an accident. Needs to be recalled ASAP. It appears that it is the lighting control module is faulty and the part itself is quite costly starting at $300 - $500 for the part itself or $800 installed.