
Condensation in taillights in the Model 3
Some Tesla Model 3 taillights may accumulate condensation, and in some cases, even a puddle inside the clear plastic cover.
Often, when submitting a service request, the service center will respond saying it is normal. If the condensation lasts longer than a day or two, be persistent and they will replace it. [ src ] [ 2 ]
Mobile service will likely be able to fix the problem or replace the taillight for you. [ src ] [ 2 ]

3 weeks old Tesla Model 3 with condensation in tail light
In the TeslaModel3 group Facebook post on April 2, 2020, Ed said his 3 week new Tesla is getting condensation in the rear taillight. src

Many of the Model 3 owners that responded added comments about how they too have experienced the issue:
- Marius: I had the same and they replaced both in Norway
- Gordon: Tesla will consider it out of specification if the droplets are a certain size and covering over 50% of the housing
- Jim: I had the same problem. Mobile came and replaced tail light very first time I asked
- Steve: Just had mine replaced. This is fairly common
- Shell: Mine had that. Tesla fixed with mobile tech really easy. No charge of course
- Miko: Mine had that the day after delivery. Made appt w Tesla Mobile Service through the app and took the tech about 20 mins to fix
- Evan: Had mine replaced for free under warranty. They even came to my house
- Jim: The tech that came out to my place told me its not normal and changed them both out and I haven’t had a problem since
- Ian: I had mine swapped out a while ago. Fog lights too. Design flaw that they fix without any problem