The drains inside the doors block up, and the water leaves not outwards but through the sill into the footwell. It goes unnoticed for a long time, because it collects in the foam under the carpet. By the time it gives off a smell, the connectors running in the floor are already corroding. Most of the electronics are under the third row, so look at the carpet there.
What to check
- Lift the carpet at all four doors and press the foam
- Open the doors and look at the drain holes at the bottom: are they blocked
- Look at the storage under the third row of seats and the spare wheel tray