Tesla did it again! On my 2014 Model S I noticed that the A/C evaporator drain dripped water inside the front end of the vehicle directly on an aluminum cross brace. It already started to corrode the part after only two months in service. I put a drain hose on the car to route the water out of the front end and outside of the car. The model 3 does the same thing---only worse. The evaporator drain is directly above the front end of the battery pack and drips water onto the pack. The location is directly above the point at which two high voltage cables exit the pack. In addition, the water ends up pooling in the steel support frame in the front of the pack and ends up soaking the front underbelly cover (which is somewhat water absorbent). The solution is to provide a drain hose out of the area to prevent corrosion damage to the steel parts and possible water intrusion into the electrical parts. You need to find a thin flexible hose that will fit into the drain. In my case I found the correct sized hose as part of a plastic pump used to fill a Kerosene heater. I cut the hose off the pump, stuck one end in the drain and ran the other end through a 5/8" hole i drilled in the front underbelly cover. The whole thing took less than a half hour to do and really cleans up the area. I wish Tesla would think about this kind of stuff when they design the vehicle. Keeping parts damp with unnecessary water isn't the best practice---if stuff gets wet, it needs to dry out. If you live in a coastal area, the evaporator condensate also has a salt concentration that steel really hates.