The Citroen Xsara is a small family car produced by Citroën, a French automaker. Though not popular in America, the Xsara was produced from 1997 to 2006 in Europe. The Xsara went through several redesigns and came in several trim levels. It was even a favourite in the world rally, winning the championship several years in a row. With that said, no car is perfect, not even the Xsara. Regular maintenance needs to be done to keep the car running normally, and this can be especially true of the headlights. Eventually, the headlight will burn out and you'll need to replace the bulb so that you can drive safely at night.
Open the bonnet and disconnect the battery cable running to the negative battery terminal. Turn the nut on the cable clamp counterclockwise to loosen the clamp and slide the clamp off the terminal.
Disconnect the electrical connector running to the headlight housing.
Pry up the rubber boot covering the back of the headlight assembly. You may need to take some time getting your fingers behind the boot, but it should come off without too much trouble.
Rotate the bulb counterclockwise to release the bulb and pull the bulb out of the housing. You may need to angle the bulb up as you are pulling it out of the housing in order to remove it.
Insert the new bulb into the housing and turn it clockwise to lock it into the housing.
Replace the rubber boot, and reconnect the electrical wiring.
Never touch the bulb with your bare hands. The oil from your fingers will cause the bulb to explode when it heats up.