I've found water on the left side of the trunk on my Golf mk4 and I'm suspecting that it's coming from the tail lights that there are not longer tightly sealed.
How can I check that? I'm thinking on just pour water over the trunk and check… but right now we have -4ºC and we are heading to -15ºC in the following days, so I don't think this is a good idea.
Is there a possibility that it's another source? Like a hole underneath? I've been checking and I haven't seen anything.
If they are finally the lights. How difficult could be to reseal the lights? I guess I need to take the lights, at lest the left one, and try to reseal with something. What something?
Background and additional info
I live in Finland, and this winter has been horrible. All the winter temperatures have been dancing around zero.
On November, I have to take the car to the shop because there was a lot of water on the trunk and washer pump just stopped working. So they told me that they changed the pump and repaired the hose that connects to the pump.
Now, I just found water again. In the beginning I thought that it was just snow and humidity and after dry pretty well the area with a small warmer I found water again after a rainy day. The waster was just water, not washer liquid like the previous time.