How to Change a Turn Signal Bulb in a 2005 Grand Marquis

The 2005 Mercury Grand Marquis came standard with a 4.6-liter V-8 engine that produced 224 horsepower. The Grand Marquis LSE came with a high-output 4.6-liter V-8 engine that produced 239 horsepower. The 2005 Grand Marquis had luxurious styling, including wrap-around, front, side marker lenses and semi-rounded taillight lenses. These side marker and taillight lenses housed the Grand Marquis' turn signal bulbs. Replacing a front turn signal bulb on the 2005 Grand Marquis requires removing the side marker lens, and the rear turn signal bulb requires removing the taillight assembly.

Instructions

Front Turn Signal Bulb Replacement

1

Open the Grand Marquis' hood and remove the three pins holding the plastic radiator shield on the front of the engine compartment, by prying the center up and out of each pin and pulling each pin from the shield. Remove the plastic radiator shield.

2

Remove the two nuts securing the turn signal assembly onto the vehicle, using a ratchet and socket. Pull the turn signal assembly from the Grand Marquis.

3

Twist the turn signal socket counterclockwise and pull it from the rear of the turn signal assembly. Pull the failed bulb from the socket, with a slight wiggling motion.

4

Grab a new 3157A bulb, using a clean, lint-free cloth and press it into the socket. The cloth prevents the oils from your hands from contacting the bulb, which may cause premature bulb failure.

5

Insert the socket and new bulb into the turn signal assembly and twist it clockwise to lock it in place.

6

Set the turn signal assembly in place on the Grand Marquis and tighten the retaining nuts to 3 to 4 foot-pounds, using a torque wrench and socket.

7

Re-install the radiator shield and insert the three retaining clips. Press the center of the retaining clips downward to lock the clips in place. Close the Mercury's hood.

Rear Turn Signal Bulb Replacement

8

Open the Grand Marquis' trunk and remove the plastic retaining pin securing the carpeting behind the taillight assembly, using a trim stick or a flat-head screwdriver. Pull the carpeting down, exposing the taillight assembly retaining nuts behind it.

9

Remove the taillight assembly retaining nuts, using a ratchet and socket. Pull the taillight assembly from the vehicle.

10

Twist the turn signal socket counterclockwise and pull it from the rear of the taillight assembly.

11

Pull the bulb from the taillight socket, using a slight wiggling motion. Grab a new 3157 bulb, using a clean, lint-free cloth and press it into the socket -- don't touch the bulb with your bare hands.

12

Install the socket and new bulb in the rear of the taillight assembly, and twist the socket clockwise to lock it in place.

13

Set the taillight assembly back onto the vehicle and tighten the three retaining nuts to 3 to 4 foot-pounds, using a torque wrench and socket.

14

Re-install the carpeting behind the taillight assembly and press the retaining pin to secure it in place. Close the Grand Marquis' trunk.