Daytime Running Lights Replacement: 1991 Mercury Grand Marquis GS 5.0L V8

Daytime running lights, sometimes referred to as DRLs or DTRs, are lights that switch on automatically when your 1991 Mercury Grand Marquis is turned on and in drive. Since the daytime running lights are on whenever you are driving your Grand Marquis, they are often the first bulbs to burn out. This video shows you how to change the daytime running lights in your 1991 Grand Marquis. You may get a warning light that the Mercury DRL system needs attention when one side of the DRL lights in your Grand Marquis is not working. These bulbs grow dimmer by over 20% over time, therefore we recommend changing both bulbs on your Grand Marquis at the same time, even if only one bulb is burnt out - this will allow both DRL bulbs to have the same intensity and prevent the old DRL bulb from appearing dimmer than the new one. You may want to consider replacing your burnt out DRL with LED daytime running lights for optimal longevity.

When you change the daytime running light on your Grand Marquis, it is important not to touch the glass part of the bulb with your fingers because the oil from your fingertips will cause that part of the bulb to burn hotter, which significantly shortens the life of the bulb. Some studies indicate that driving with your lights on can reduce accidents by 18 – 34%, driving with your DRLs or headlights on the day can reduce your chance of getting in an accident.