I think it happend because i had to open my trunk to get stuff out a couple times while it was raining. There is a taillight cover that looks like some water could seep into the taillight while the trunk is open (just a guess)

My thoughts are...

Take the taillight off, inspect for worn silicone or gaps or holes in the seal. (add touchup silicone for a better seal)

If the seal is infact worn or crumbly or what have you, Use the oven method to take the housing apart from the lense and replace the sealant.

This is my Daily

Any thoughts will be grealty appriciated.

2005 41k