Stinky interior? Is your Model 3 starting to smell moldy, especially when you turn on the fan?
After running the air conditioner in the M3 and exciting the vehicle, condensation forms in the climate control system. Also, with cabin overheat protection enabled, the AC will automatically be turned on and off.
If someone is having this issue, a (possible) way to fix this is to turn off the AC at your destination and let the fan run 3-5 mins before turning off or leaving the car. Also make sure to turn off COP or switch it to “No AC” mode.Reddit user Lancaster16
Apparently there was a firmware change somewhere during 2019 that fixed the issue, and some owners have been able to take their Model 3 into a service center to have their A/C condensor system cleaned (and perhaps fixed?)
Tesla also recommends running a/c in ‘fresh air’ mode, never on recirc.
Sometimes it seems covered under warranty, other times, it isn’t. One Model 3 owner reported the cleaning was covered, but a replacement air filter wasn’t.
Early adopter here. In the early models, there was some kind of A/C condensate drain issue that caused this. I assumed it’d be a warranty issue, but was billed as the guy wrapped up. I had to pay Tesla about $140…[they] had to partially disassemble the center console to get at it, tinker with things, and replace the filter. Haven’t had the problem since.Reddit user mdjmd73
I had mine done in August  and Tesla service came to my house and cleaned the condenser and replaced the filter for free. They also replaced my charging port with a revised part. It was the easiest car service of my life.Reddit user Iloveturbocars_22
I paid $150 for evaporator cleaning and new filters back in August . They refused to comp it even though they admitted a software problem (with the “auto” A/C setting) caused premature mold/bacteria buildup on the coils.Reddit user TurboBearNC