The 2005 Ford Taurus uses composite halogen headlights. This means the bulb inside the headlight assembly can be replaced instead of replacing the entire headlight assembly, which was necessary on many older cars with sealed headlights. Since you only have to replace the bulb, the process is simple and inexpensive. A replacement bulb is available for less than $5 in most cases. Halogen bulbs are sensitive, so don't touch the glass area of the bulb with your hands; hold it by its socket only.
Shut off the Taurus's engine and headlight control switch. Open the hood to access the top edge of the headlight.
Find and remove the bolt in the top-center corner of the headlight. Use an open-ended wrench or a basic ratchet.
Look at the rear edge of the headlight and find the two metal prongs. These prongs are the final pieces of hardware holding the headlight in place. Pry them up with pliers to remove them.
Pull the headlight out to access its back cover. Twist the dust cover on the back counterclockwise to remove it and then unplug the electrical connection.
Turn the bulb mounting ring counterclockwise to unscrew it. The bulb is now visible. Pull it straight out.
Push the new bulb into place. There is a notch on the ride side of the bulb mount. Be sure the prong on the side of the bulb socket goes into the notch, or the bulb will not fit correctly.
Replace the bulb mounting ring. Turn it clockwise to twist it back on. Plug the electrical connection into the rear of the bulb.
Attach the dust cover and turn it clockwise to screw it back on. Place the headlight back into place.
Insert and tighten the bolt. Insert the two prongs and push them down firmly to secure the headlight.
