befor eyou go out and buy new tail lights.

mos tof the time there is a small spongy washer ont heback of the lights. where the bulb gose threw .
and over time and as we replace bulbs some for get to put them back on . OR they tear and we dont think we need them .

this is the same thing that dose it in head lights also.
but worth a shot.

 

Mine does it too, every time it gets a bath. Doesn't have to be cold. It's drizzly and cold right now but I'm not going out to check, I'll try to remember in the morning to look.

 

Mine does it every time it gets cold. Once final exams are over (tomorrow! yay!) I'm going to check the gaskets on the lamps to see if they have been damaged or are suffering from dry rot.