The BMW E34 features composite headlight bulbs that can be replaced without having to replace the headlight itself. If your headlight is cracked or worn and to foggy to let through good light, it may need replacing. Fortunately, replacing the headlight on a E34 is a rather straightforward procedure, although it takes a lot of patience and strength to achieve. Extraneous parts to the headlight have to be removed in order to remove the headlight. Despite these challenges, replacing the headlight shouldn't take you more than an hour, so long as you don't break anything in the process.
Turn off your E34 and prop open the hood.
Shine your flashlight through the column of holes on the rear of the low beam headlight, the portion of the assembly near the centre grille. Stick your flathead screwdriver through this column of holes to reach the retaining tabs holding the grille in place.
Press against the tab at the bottom of the column of holes with the head of your screwdriver. Press when you feel the screwdriver hit a springy object. Face the head of the screwdriver toward the front bumper. Repeat this step for the other side of the grille.
Wedge the flat end of the flathead screwdriver between the wing of the centre grille and the headlight assembly and pry the wing upward. Continue this process on both sides of the grille until the grille is loosened enough to lift out of its cavity.
Remove the three long screws on top of the headlight as well as a fourth long screw holding the turning signal portion of the assembly to the bumper.
Unplug the wiring harness from the rear of the headlight and lift the headlight out of its socket. Repeat the prying motion you used on the grille with the headlight if it is stuck.
Insert the replacement headlight into the position where the old headlight was. Remount the four large screws you took out earlier, and set the grille back into place.