Each DeLorean door has three lights, two amber at the front and side and red at the rear. The factory installed incandescent bulbs can draw enough power to drain a battery if either or both doors are left open or ajar.
A popular upgrade is the replacement of these bulbs with their LED equivalents. DMC (Texas) has a kit of all the door lights and these can be installed quickly and easily as shown in the video below.
NOTE: LED bulbs will only work when inserted in one direction. If you install a bulb and it does not illuminate, remove it and rotate 180 degrees and reinsert.