My Yeti fog light lens has swollen like it has melted. I have not used the fog light for a long while so I can't see how the daylight driving bulb can cause this. I suspect it has been hit by a stone but there is no obvious external damage.

http://s1278.photobucket.com/user/steveh1600/library/Yeti%20Fog%20Light

I am not getting any water ingress so it is not a problem, but it will be expensive to fix as the fog light and headlight lens are one part.

Has anyone seen this before on a light lens or any ideas what has happened here?

Steve

I wonder if you have beaten odds of millions to one and somehow had a freak situation where strong, direct sunlight has been reflected and focussed by the headlight reflector and overheated the lens?  It does look like it has been overheated and I assume your bulb(s) is/are the standard power fitment.

Bulbs all standard. When you run your finger over the lens it is a bump in the lens. Weird.

Certainly is weird. Even if the bulb got really hot I doubt it would have caused that as the light wouldn't have focused like that.

 

Weasley might be onto something, as improbable as it sounds. 

 

Or could it be that something has been spilt onto it or an external heat source has been applied? Grasping at straws I know!

Maybe some sort of chemical has caused it ?

I just don't get it either. Thanks for your comments . If I get water ingress then I will have to stump up for a new headlight unit.

Vandalism by cigarette lighter?

Strange but interesting.

As said above, possible damage from outside the lens caused by focused sunlight.

Doubt the damage came from the bulb as is concentrated off centre.