S-10CREWCAB.NET

is there a way to test it like with a vacum tester or something ?? it's 110 bucks i'd like to know if its bad before i buy a new one

my 2000 s-10 4x4 zr4 has the hissing noise coming from the dash and can't switch the vent stuck on face blow , if I plug the t/c vacuum line will it stop the hissing,,and so far I haven't found trans fluid in the vacuum lines how can you pin down the problem down with out RR each of the switches?? i...