Fixing Leaky Forward Clearance Lights.
Recently I noticed that one of my forward (Yellow) clearance lights had a burned out bulb, so I scrambled up on the roof to replace it. Unfortunately, I discovered that the light had water inside of it. So like my tail light saga, changing a bulb is going to result in a major repair.
In an attempt to fix the leaky lights, the factory (or dealer as we bought the coach used) gooped some sealant on the screws of each of the lights. This sealant was very difficult to get off as it reminded me of 3M 5200 that is popular with boats. I doubt 5200 was used, but anyone ever hear of silicone sealant? Silicone would be appropriate here as not only waterproofs, but it is fairly easy to remove.
So after chiseling the goop off the tops of the screw heads, I was able to finally remove the bezel... and it was then I realized how stupid these lights are.
From the photo to the right, you can see that the entire area under the lens leaks, as evidenced by the mold around the gasket.
As well, you can see where the light socket itself has some corrosion on it, again more evidence of leaking. I plan on using some dielectic grease here to ensure a good connection when I complete the repair.
Fortunately though, it appears the factory used some kind of sealant under the screws attaching the light fixture to the roof, so at least I won't have any issues with roof damage.
I have to believe the designer of these lights has no concept of how water sheds off a roof or siding as you should have an overlapping joint, not a cup.
From the conceptual drawing, you can see how the light sits inside of the cup. Also, the conceptual drawing shows how the lights should have been designed if preventing leaks was a high priority.
The only way I know how to fix this, without replacing all of the light fixtures, is to get rid of the gasket and silicone seal both under the screw head and around the "cup" that the lens sits in.
Unfortunately, that presents another problem... changing out burned out bulbs. So to alleviate that, I plan on upgrading the light bulbs to LED equivalents. Hopefuly by using LEDs, I will never have to change out a bulb again, and can seal the light fixtures with silicone sealant.
The bulbs in my fixtures are common #67 incandescent automotive lights.
I did find a LED replacement that has about the same intensity, and is almost the same size. While the LED replacement is slightly longer, there is adequate clearance under the lenses for it to fit.
The most noticeable difference is the LEDs have a daylight color temperature while the #67 bulbs, like most incandescent bulbs, are a warmer color that results in a more "yellow" light. This is not an issue for me, but you can buy the LEDs in Yellow if you want more of a yellow result.
To re-assemble, I got rid of the foam gasket, and ran a bead of Silicone around the perimeter of the light fixture to seal the lens. I then #60 plumbing O-Rings and a washer under the screw heads when re-attaching the lens.
I also used stainless screws and washers. I had to increase the length of the screw to accomidate the O-Ring (I used a #8 3/4" screw), and found that a #6 washer will still fit a #8 screw, and will provide a better surface for the O-Ring than a #8 washer.
Hopefully this will permanently fix the leak problem.
The RV industry never ceases to amaze me... and I say that with all due criticism. Who in their right mind would design a forward clearance light that leaks?
Items I used in this repair: