1996 Ford Aerostar Owner's Manual - Page 303

Installing the headlamp bulb 1. With the flat side of the bulb's plastic base facing upward, insert the glass end of the bulb into the socket. You may need to turn the bulb left or right to line up the grooves in the plastic base with the tabs in the socket. When the grooves are aligned, push the bulb into the socket until the plastic base contacts the rear of the socket. Snap the retaining wire over both sides of the bulb and connect the electrical connector. Position the headlamp on the vehicle and install the four attaching screws. Turn the headlamps on and make sure that they work properly. If the headlamp was correctly aligned before you changed the bulb, you should not need to align it again. 325 2. 3. 4.