Moisture in Taillight : Gasket or Light Itself

[dog2bert]

My rear outer taillight is starting to show some moisture. Is this the gasket or the light itself?

My side marker light is also showing some moisture even though I just replaced it.

[cobra]

The gasket keeps water from getting into the car, so if it's inside the tail light then the light is compromised.

[Pklauser]

The gasket keeps water from getting into the car, so if it's inside the tail light then the light is compromised.

The back of the light is open though. If the gasket fails it'll allow water to run down the back and into the light.

OP: I'd start with the gasket.

[Wernd]

Keep in mind there's a foam gasket that helps keep water out of the light itself but there's a plastic & rubber gasket that helps keep water out of that general area to begin with

[Dash1]

Most likely the clear outside cover is delaminating from the housing. Your best bet is to buy a new taillight

[Tbonem3]

The clear/red plastic on these lights separates from the backing plastic fairly easily. In my experience, that's what lets moisture into the light itself. I sealed it up with clear silicone, wiping away excess, on an older (prefacelift) car I had. My led (2004) ones haven't had an issue.

[Arith2]

The clear/red plastic on these lights separates from the backing plastic fairly easily. In my experience, that's what lets moisture into the light itself. I sealed it up with clear silicone, wiping away excess, on an older (prefacelift) car I had. My led (2004) ones haven't had an issue.

I've sealed two tail lights this way with no issues.

[dog2bert]

Have any pictures of doing the re-sealing process?

[Thoglan]

I've done the same thing. Just run a bead of clear silicone around the lens area thats leaking and let it set. Make sure the light is completely dried out though, any moisture still in the unit will cause it to continually fog up. Better to do it sooner rather than later too since a surprising amount of water pools in them if it's leaking a reasonable amount which eventually contact the board and start killing LEDs

[pynacl]

I’d also start simple with the gasket. Definitely get on it as soon as possible before it leaks and pools in your battery tray. If standing water sits in there it’ll rot the floor panel. I spent a good day or so cleaning up that mistake on mine

[dog2bert]

I finally replaced the taillight. The gasket seemed okay it was the lens that failed. I couldn't believe how much water came out and it still worked fine.

[dog2bert]

I also replaced the side marker light. Has anyone had any luck sealing somehow to make it last more than a year. With FCPEuro its fine, just annoying.

BMW Side Marker Lens - Magneti Marelli 63137165845