This morning the car was slightly frozen so I did the usual - heating on, A/C on, everything set to clear windscreen and rear window heater on. It took the car just over 5 mins to clear the windscreen, however I noticed the rear window did not seem to be clearing at all. Then I put on the rear wiper and discovered the window was covered in water on the inside! As soon as I touched it, a stream of water ran across the glass. I am assuming this moisture is getting in from those times when i open the boot lid during the rain. However, what is the recommended way of clearing this (and keeping moisture to an absolute minimum)? 

Edited 4 November, 201312 yr by cs.rogers

Unless it was really raining and you left the boot open for a long time then rain won't account for that much water. Have a look in the spare wheel well to see if there's more water. Also check if you have windscreen washer fluid rather than water evaporating in the boot. The washer fluid pipe has a connector that sometimes pops off in the left side of the boot behind the side carpeting and sprays fluid into the space there. A very quick check is to see if the rear washer works, if everything sounds right and there's no spray the fluid is probably going somewhere else.

 

More annoyingly there's an earthing point in that corner of the boot under this join, and when I had this happen there wasn't even enough fluid to make it into the boot, but got the earthing point wet and made by dashboard light up like a christmas tree, 19 separate modules were giving errors and the ABS turned off. Luckily someone on this forum diagnosed it and 3 sheets of kitchen paper later, the earth point was dry and the car was back perfect...

 

The seal around the boot leaks sometimes too - I found the round part of mine filled with water from somewhere, possibly the dip between the flat part above the tail lights at the back of the boot and the back window, which makes a corner that can collect water if you park the car pointed downhill. I made a couple of small holes in the outside of the seal at the boot lip and the problem disappeared, but I never saw water making it into the boot through this route.

 

Then again my parking sensors only work when it's hot and dry, so less than 2 weeks a year in Ireland, so it does suggest I still have some kind of water problem somewhere...

 

To get the car back dry once the source of the water has been found, I'd suggest leaving a dehumidifier running in there for a few hours.

Edited 4 November, 201312 yr by psycholist