[pole1980]

I kept finding suspicious water spots on the roller blind inside the trunk, today I finally found the cause.

The water gets in around the third brake light, tested this with a hose, bam, water seeps in, then pools in the trunk.

Apparently the seal around the lamp went bad, god knows why, and the seal (which is actually not a seal but an adhesive tape) can't be replaced, so I had to order a new third brake light, for the insane amount of 200 USD, which I will try to fit myself.

So there you go, if you are finding water spots in your trunk, this could very much be the reason. Mine is a 2016 X3.

[pungo]

Curious why the adhesive tape can't be replaced with a similar product? I would have tried some Butyl Sealant Tape before spending the $200 on a new light assembly

[deyrag]

Had same thing a few months ago. I just pulled the light out and ran a small bead of black silicone (have black car) around the edge, re-installed and been leak free ever since.

[ramda2021]

I have noticed some water drops pouring down inside from the edges of the trunk door only when I'm opening it, it didn't seem to happen before. I wonder what could solve that.

[bmwPower99]

Originally Posted by radanmih

I have noticed some water drops pouring down inside from the edges of the trunk door only when I'm opening it, it didn't seem to happen before. I wonder what could solve that.

I had the same issue it's third brake light seal letting water in and/or the wiring loom next to the tail lift gas struts letting water in. As mentioned earlier both can be fixed by a bead of outdoor spec clear silicone round the edges.

[pole1980]

Originally Posted by bmwPower99

I had the same issue it's third brake light seal letting water in and/or the wiring loom next to the tail lift gas struts letting water in. As mentioned earlier both can be fixed by a bead of outdoor spec clear silicone round the edges.

can you please detail the wiring loom issue and where to apply silicone? a picture maybe? thank you

[bmwPower99]

Originally Posted by pole1980

can you please detail the wiring loom issue and where to apply silicone? a picture maybe? thank you

Difficult to see but there is clear sealent round the entire third brake light. Water ingress from here makes it into the tail gate and then drips onto the shelf below.

You can also see sealent round the wiring loom for the tail gate. I had water getting into that and making its way to the fuse box area in the rear right.

[pole1980]

Originally Posted by bmwPower99

Difficult to see but there is clear sealent round the entire third brake light. Water ingress from here makes it into the tail gate and then drips onto the shelf below.

You can also see sealent round the wiring loom for the tail gate. I had water getting into that and making its way to the fuse box area in the rear right.

Oh, so you applied sealant around the third brake light without removing it? Shit, I should have done this before paying for a new brake lamp...

Thanks for the pictures.

[bmwPower99]

Originally Posted by pole1980

Oh, so you applied sealant around the third brake light without removing it? Shit, I should have done this before paying for a new brake lamp...

Thanks for the pictures.

That's right, all done without removing the light.

[pole1980]

Originally Posted by bmwPower99

That's right, all done without removing the light.

You must have surgeon's hands how did you manage to spread it so even and clean?

[bmwPower99]

Originally Posted by pole1980

You must have surgeon's hands how did you manage to spread it so even and clean?

Lol, I honestly can remember, it was a few years ago.
Perhaps I used masking tape, that would be the safest bet. You can see some silicone smudges on the bottom left of the light I had a bit all round the light but it buffs out.

The silicon that I bought in the UK was a bit pricey but it advertised itself as 'crystal clear'. That is a must in my opinion as well as being outdoor spec.

[Mircea97]

if i take out the brake light and put clear seleant will there be problems? just cant find a video of how to get the light out, i press the metal pins but nothing.. dont know what the close/open does on the light ...

[bmwproblems925]

okay so, I noticed signs of water after a heavy rain on my trunk mat and a pool of water in the compartment next to it. I opened up the battery compartment to check and there was water there as well. I cleaned it all off and tried to find the source of my water leak. it is from the third brake light. I sprayed water on it and water came dripping out from both sides.

I was rear-ended, and the body shop replaced the whole trunk. They mentioned a lifetime warranty on the work, does this apply?

[frisbeeguy]

Originally Posted by bmwproblems925

okay so, I noticed signs of water after a heavy rain on my trunk mat and a pool of water in the compartment next to it. I opened up the battery compartment to check and there was water there as well. I cleaned it all off and tried to find the source of my water leak. it is from the third brake light. I sprayed water on it and water came dripping out from both sides.

I was rear-ended, and the body shop replaced the whole trunk. They mentioned a lifetime warranty on the work, does this apply?

Yes, take it back.

[bmwproblems925]

Originally Posted by bmwPower99

Difficult to see but there is clear sealent round the entire third brake light. Water ingress from here makes it into the tail gate and then drips onto the shelf below.

You can also see sealent round the wiring loom for the tail gate. I had water getting into that and making its way to the fuse box area in the rear right.

are you still around?

how are the sealants holding up? any rust damage?

[bmwPower99]

Originally Posted by bmwproblems925

are you still around?

how are the sealants holding up? any rust damage?

Third brake light is holding up. No water on the parcel shelf roller but just in the last few weeks I've noticed water here https://x3.xbimmers.com/forums/showthread.php?t=2083479

I'm curious as to how you think the brake light is causing water in the battery area? Surely
the parcel shelf first and then the plastic tray on the boot floor would pick up all the water?