When the headlight bulb in your Mercedes S430 burns out, you need to replace it with an H7 replacement headlight, available at most auto-parts stores. Headlight failure on the S430 happens over time, and there is no specific service life for these bulbs. When replacing your S430's headlight bulb, it's a good idea to replace both headlights. The reason for this is that both headlights will have the same amount of hours on the bulb. When one burns out, the other will likely follow soon.
Open the hood and unplug the electrical connector running to the back of the headlight. Squeeze the tabs on the connector and pull them off the headlight.
Pull the dust boot off of the back of the headlight with your fingers.
Grab the headlight at the base, called the "collar," and rotate the headlight counterclockwise to unlock it from the headlight housing. Then, remove the headlight from the housing.
Install the new headlight. Make sure that before you attempt to secure the headlight to the housing by turning the headlight bulb clockwise that you have the tabs on the headlight collar aligned with the notches in the back of the housing, and that the front of the collar sits perfectly flush with the headlight housing. Installation is the reverse of removal.
