I discovered that my passenger side foglight has a broken lens with about a 1" diameter hole. The bulb is still intact. This is one of the "Yaris" foglights that I installed last year. The lens is plastic, about 0.15" thick. One thing that's annoying about these is their very diffuse beam pattern. They have aiming screws, but the beam alignment procedure is a waste of time - beyond 3 - 6 ft, the beam is so diffuse that there's nothing to aim. I'm thinking about buying the OEM light rather than getting another Yaris kit (or the individual lights), but I'm curious if people with the OEM lights find them just as difficult to aim or do they have a better pattern.
Both mine are cracked as well but no hole or moisture inside the units yet. I plan on getting another Yaris kit but this time put some of the clear film on them to prevent the cracking. I thought the ones I have aimed rather well and had a pretty defined beam @ 5' or so.
oem foglights adjust very easily with a phillips screwdriver. Just stick it up through the hole in the plastic cover underneath the bumper, feel for the slot and turn the screw to adjust the foglight vertical tilt. I was looking at some Yaris foglights that a friend had and compared them to my oem foglights. It looks like the oem foglights use a thicker tempered glass, where as the Yaris foglights use a thinner non-tempered glass. Pretty much similar to when you get a new windshield, if you get an oem one that's made in the US (or Japan for the Prius), then it's a good quality piece of glass. Where as if you buy the cheap 'made in china' windshield that sometimes looks blurry and is not tempered, it can and will crack easily. It looks like that's how the Ebay Yaris foglights (which are made in China) compared to the oem Prius foglights. Just an observation I made, unless somebody has some additional info they want to add. Next time I'll see if I can take some pictures, and see if there's any way to show a difference between the glass (but you can feel it when you tap it and look at the contour of it).
The Yaris adjustment screws are pretty stiff, and I've had trouble getting the right size phillips screwdriver - a #2 will slip in the screw head, but a #3 is a bit too large . . . and if you try to follow the official aiming instructions (distances of approx. 25 feet from vehicle), there's no definition at all in the pattern. The Yaris lenses are plastic, not glass. I suspect the OEM lights are thicker, polycarbonate lenses. It would be great if you could compare the beam quality between your vehicle and your friend's at 25 feet, say park both vehicles facing a wall at night. That's the kind of info I'm seeking.
FWIW, the aftermarket Yaris lenses are glass. I know because I broke one of them. However, they don't seem to leak after they crack.
I was wondering the same thing too; my Yaris fog light kit I bought in eBay is not plastic, it is glass too.