Corrected entry: When the Americans first board the U-571, they are looking for the "Christmas Tree" which is a series of red and white lights. When they first see it there is a red light on, however when they turn back to it seconds later all the lights are white, or clear. (00:51:15)
NyQuil
12th Sep 2002
Correction: Since they were preparing the boat for dive, the light could have cleared between shots.