I have problems starting the Toyota 4 Runner. Can a leaking windshield affect?

Hello, it would not per normal for a leaking rear window to cause a battery concern, however, if something is keeping engaged when the vehicle is off otherwise, it could be that some kind of "parasitic draw" is draining your battery. This can be checked by seeing if there is a draw on your battery when off. If so, you can determine which circuit is staying "alive" by removing fuses until the draw goes away. You may wish to seek professional guidance for this.