I've posted about this elsewhere, but in case anyone finds this thread, I now know how the water gets into the passenger footwell and causes these problems (even when the drainpipe is clear):
The passenger side bonnet grill (UK car) has a water drainage system. Rain water that goes into the grill goes down a pipe, through a soft corrugated rubber nozzle, into a funnel that is moulded into the plastic wheel-ach liner. From there it goes out through the liner into the wheel arch.
The rubber nozzle is to slow the speed of the water so that it doesn’t splash over the edge of the funnel, if it does, the water runs down into the passenger foot-well, under the carpet.
The problem is that the system works ok with rain, even heavy rain, but it can’t cope with a car-wash or jet-wash and huge amounts of water ends up under the passenger carpet. Unfortunately, under the carpet are several electrical connector blocks for the cars systems ECU; things like warning lights, roof control etc. These end up under water and all hell breaks loose.
The solution is to remove the passenger seat, remove the trim and then lift the carpet. You then need to dry all the water out. Then unclip the top of the black electrical cable conduit and dry everything inside. Ideally, take the plugs out of the block connectors one at a time and blow them dry with an airline. Then put them back with a little electrical silicone grease which will protect the contacts and drive out any remaining damp.
Drying the underside of the carpet is a real pain in the ass because it has thick soundproofing foam on it which will be sodden. Leaving the seat out, the carpet held up on block with a heater in the car for a couple of days may be the only answer.
Once this is all done, you can put everything back and it’ll be fine. However, you’ll need to block off the vent in future when you wash the car – it’s a crap design I know, but there it is
The passenger side bonnet grill (UK car) has a water drainage system. Rain water that goes into the grill goes down a pipe, through a soft corrugated rubber nozzle, into a funnel that is moulded into the plastic wheel-ach liner. From there it goes out through the liner into the wheel arch.
The rubber nozzle is to slow the speed of the water so that it doesn’t splash over the edge of the funnel, if it does, the water runs down into the passenger foot-well, under the carpet.
The problem is that the system works ok with rain, even heavy rain, but it can’t cope with a car-wash or jet-wash and huge amounts of water ends up under the passenger carpet. Unfortunately, under the carpet are several electrical connector blocks for the cars systems ECU; things like warning lights, roof control etc. These end up under water and all hell breaks loose.
The solution is to remove the passenger seat, remove the trim and then lift the carpet. You then need to dry all the water out. Then unclip the top of the black electrical cable conduit and dry everything inside. Ideally, take the plugs out of the block connectors one at a time and blow them dry with an airline. Then put them back with a little electrical silicone grease which will protect the contacts and drive out any remaining damp.
Drying the underside of the carpet is a real pain in the ass because it has thick soundproofing foam on it which will be sodden. Leaving the seat out, the carpet held up on block with a heater in the car for a couple of days may be the only answer.
Once this is all done, you can put everything back and it’ll be fine. However, you’ll need to block off the vent in future when you wash the car – it’s a crap design I know, but there it is
