On '01 Blazer, I was replacing old brittle vacuum lines tonight and came across this vac switch and realized being tucked under the A/C Low Pressure port is not where this thing is supposed to live.....particularly when I noticed the mounting tab at the bottom. Any help as to where the proper mounting point is would be appreciated.

 

Think its almost dead center of the upper firewall

 

Thanks Newguy, but it's the other very similar looking vac switch that apparently resides in the vicinity of passenger side of the engine compartment.