Then you have to add to the formula, what the previous owner (s) did. We were the thrid owner of ours and I think that the first owner had it a couple of year and then the second owner had it 10 years. So in the time the second owner had it, I think a few of the stock items had been change out. I know I don't have the original inverter and dash air compressor. Each time someone touches these bus's including me, it does not follow the original diagrams. This is why the network of bus owners is so nice to have, plus the friends you make.

It is really important that a bus owner try hard to understand each of the systems on their bus.