Interior Lights question 1988 XJS

I just purchased my first XJS and have a question that I hope someone in this user group may be able to answer. When I open the doors, two white lights on the bottom LH and RH sides of the dash board (about 3" long x 1" wide) light up the foot wells. When I Press the button the dash board (to the right of the clock) to manually light up the foot wells only the right side light illuminates. Is this normal? Thanks, Rick Piatt