Yes, the fogging is definitely on the inside. Here are a couple of photos. As I said, on the last trip only the passenger side was fogging from the beginning. We were having trouble getting the genset to start so we stopped in a rest area to check that out. I let the engine run for about 15-20 minutes to keep the dash air going while I worked on the generator. When we departed, the drivers side camera was also fogged. It appears the cause is outside humidity and engine heat as the cameras are mounted next and open to the engine compartment on the back. Liquid water isn't an issue but water vapor certainly seems to be.