Troubleshooting Trailer Clearance Light that Leaks Water

Updated 03/23/2026 | Published 03/17/2026

Question:

My 2022 Airstream Basecamp 20X has rear marker lights over the rear hatch. The Airstream part number is 513026 and looks like the Optronic MCL10RKB or a variant. The lights are working fine. I suspect that the installation or grommet is leaking water into the wall of the trailer after a recent very heavy rain. We discovered water leaking into the interior under the lights. I duplicated it with a sprayer today. Do you have installation instructions that describe the preferred way to ensure a water tight installation to prevent water leaking into the trailer when installing it? Shall I just caulk around the 4 year old grommet or replace it with a longer lasting grommet? I do understand that the plastic LED module is water tight, but I also need to ensure the no water passes into the wall of the Airstream past the led/grommet edging after the light is installed. Thank you, Dan Hilsdorf

asked by: Dan H

Clearance Light
(click to enlarge)

Expert Reply:

Hey Dan, thanks for the picture! From that I can tell you have the part # MCL10RKB or like you said one of the variants which are essentially the same thing. The only way you'll be able to improve the water proofness will be to caulk around the grommet and the light assembly although I suspect it's the grommet that just needs to be sealed. Do any of the other lights leak at all?

expert reply by: Jameson C

Dan H.

3/18/2026

I’m not sure about any other lights, but spraying the hose on the center light quickly resulted in water inside below the light. I had been spraying all 3 over the hatch. What’s the best caulk/sealant to put around the grommet where it meets the aluminum?