MT Auto Parts Blog | Expert Tips for BMW enthusiasts on BMW Parts, Accessories, Engines and More

Photo by Tim Meyer on Unsplash A wet footwell in a BMW is one of those problems that tends to get worse the longer it is left. Water sitting on the carpet soaks through to the underlay, creates a damp smell that is very difficult to shift, and, most seriously, can reach the footwell module (FRM), the small but critical control unit mounted under the driver's side dashboard. Once water gets to the FRM, what started as a leak becomes an electrical fault. Here is where to start looking. Blocked or Disconnected Sunroof Drain Tubes This is the most common cause of a wet BMW footwell, and it affects cars with a sunroof or panoramic roof. BMW sunroofs are designed with drain channels at each corner that carry water away from the roof seal and out under the car. When these tubes block with leaf debris, algae, or sediment, which happens gradually and without warning, water backs up and overflows internally rather than draining away. It typically ends up in the footwell on whichever corner t...

  Image: BMW 5 Series (F10) Complete Sunroof SERIES COMPLETE SUNROOF for £141.85 at MT Auto Parts     Water inside the cabin of a BMW is one of those problems that gets worse the longer you ignore it. A damp patch on the headliner becomes a wet footwell. A wet footwell becomes a corroded module. A corroded module becomes an expensive repair that traces back to a blocked drainage tube that could have been cleared for almost nothing. BMW panoramic sunroofs are one of the more common sources of water ingress on UK cars. Not because they are badly made, but because they rely on a drainage system that most owners do not know exists, and therefore never maintain. How the Drainage System Works — and Why It Matters The BMW panoramic sunroof is not a sealed unit. It is designed to let a small amount of water past the glass seals during heavy rain, then channel that water away through four drain tubes, one at each corner of the sunroof frame, that run down through the A and C...