Hi. Found the drivers side windscreen piller soaked today. Car is parked so water would mostly run towards this corner of the car. I am presuming that drain channels are blocked but where are they all and are there any other known leaking points on the roof?

Thanks

James

Hi,
I had the same problem.
The sunroof drains run inside the A and C pillar and are very difficult to get to, to clean them out you will need to remove the A pillar cover on the inside then the sunvisor and headliner light unit and carefully remove the headliner making sure not to bend it.
You will see the drain pipe which can then be removed and blown out, dont do it from the sunroof even though it is easier as it can blow off the pipe and you will need to go through this operation anyway.
I found my problem to be the screw holding the airbag in the A pillar...it is a very long and sharpened which when installed it pierced the drain pipe in the A pillar and until recently had "sealed" the pipe until recently when it started leaking due to blockage.
I eventually ran a new hose from the sunroof down the A pillar behind the cover into the foot well and out a hole behind the pedal box to exit outside the car.
Remove the alu sill protector and lift the carpet and suck out the water accumulated in the channel carrying wiring to the rear of the vehicle to avoid corrosion.
Also remove and spray WD20 into the connector attaching the drivers door electrics into the car, these get wet, corrode and then you lose function of the window controls and the mirrors do their own thing!