While washing my MCS last night I noticed the tail light on one side had a lot of condensation in it. I'm assuming that this is bad. Am I correct? I'm taking her in for service tonight anyway, is this something they should be fixing?

 

I get condensation in the center reverse light sometimes as well.

 

I'm on my third or fourth center break light because I kept getting condensation in them. I get it in this one, too, but now I'm just tired of having it swapped out, so I'm leaving it. It isn't much, and I doubt it really does much harm. I live in SoCal so it's not like I'm in wet or humid weather very often...

 

In most cases, it's a faulty seal allowing moisture in. It will be replaced under warranty. See if you can duplicate it for the dealership prior to your visitation if your dealer is the **** type.
I had that issue on my SVT Lightning. The lights were swapped out without question when they saw them fogged up after I washed it prior to showing up.
Cheers,

 

It is not a good thing for moisture to get behind most lens.