I am at the same place as you, does a bad aux pump short the control unit out. I spent 2 hours last night trying to figure out what to do next. On my 126. the first wall behind engine seems to have 4 screws that will alow me to remove a panel, that will give me room to replace aux pump. that is my next move and repair kit for mono valve, I could not do this with out the help here, thanks everyone steve