Clogged drains can allow rainwater to accumulate in the plenum tray (at the base of the windshield). The water may leak into the vehicle's interior, brake booster, or electrical components, which can lead to major problems. Our technicians recommend keeping the tray clear of leaves, pine needles, and other debris.Google+
Car Problem Reports
Audi S4 Rainwater May Accumulate in Plenum Tray Due to Clogged Drains
Audi S4 Problem
Visitor, 2004 Audi S4, 151,000 mi
after a heavy rain, i discovered water in my drivers side floor and the electrical system is all screwed up. Blinkers and wipers first worked intermittently and now not at all, the rear brake lights stay on even when the car is turned off, and now the headlights stopped working. Any suggestions besides cleaning my drain plugs to prevent this from happening again?