Condensation in boot driving me loopy

[ABToyota]

So I had water in the boot and I narrowed it down to the passenger side rear light cluster - the seal had failed. Everything I thought was fine but then I noticed that the cloth in the boot was wet and there were droplets of water condensation on the spare tyre. 

I took the cloth cover out and let it dry. Checked again and the boot was bone dry. I replaced the cloth cover and  a few days later it was again the same dampness like condensation is collecting. 

I have looked at the rear vents and they are dry on both sides. So what is causing this condensation / dampness?

[furtula]

There were several topics related to this, use search and check the issues from there, some might be related.

[ABToyota]

2 hours ago, furtula said:

There were several topics related to this, use search and check the issues from there, some might be related.

I did and they all pointed to either gasket behind the lights or the vents. 

But then why does it only happen when I have the boot liner down and not when its removed?

Also can someone tell me how do I remove the plastic coverings in the boot - I bought a tool off eBay but I can't see any pushpins to remove.

[Gerg]

I'm not sure as to what you have already taken off , as you say about seeing both sides of a vent. 

I don't own a Mk1 Auris, but this document (courtesy of eygo) shows how the boot trim comes out.  Note that this is in the section 'Headlining removal'!

http://www.autocats.ws/manual/toyota/auris_corolla_zze-zr-nde-ade/rm04f0e/repair2/html/frame_rm000002w9e000x.html

On a MK2 you don't have to remove the boot trim (as this manual describes), at the seat end, as it will swing out enough to allow you to see behind it with the seat end still connected. But if uncertain, best go by the guide.

If the bumper needs to be removed then the same document will help for that too.

Alternatively, this bumper removal video is for a US 2009 Corolla sedan, but it is almost certainly very similar, and gives some useful hints as to the bumper flank detachment from the body.  It is certainly very similar to the removal in a Mk2 Auris.

 

On a Mk2 Auris (pictured), there is an air vent on the rear  that looks as if it is vaguely near your leak.  It is interesting how the 'witness' marks from the rain water seem to go to it.  That must be a lot of water flow, relatively.  I have no idea if the Mk1 is the same.

If the boot trims are removed, then you need some way of detecting small amounts of leakage.  I read somewhere people use talcum powder somehow.  But, off the top of my head, why not buy some cheap, coloured, paper napkins;  the ones that go dark as soon as they get wet.  And use those to feel around any fixtures and fittings to check for damp.

You may have to run a hose over the back of the car (after it has dried) and then check for damp soon after, or even lie in the boot with a torch while someone hoses the car.

The effects of capillary action when dealing with water leaks mean the unlikely-looking imperfections can draw plenty of water, especially when there is something to wick it away on the inside.  If you think you have spotted a potential leak, I suppose you could seal it temporarily with White-Tak (or Blutack, but I think that is a little harder).  I have never tried this, but I see no reason why it shouldn't help you cover up a dodgy looking bung etc. to check a diagnosis.  And it's really cheap and doesn't smell.

In my Auris the sealant in the doors looks like it was put on by someone from pre-school, it's a real mess. 

Good luck.

HTH.