Are diff lock switches reliable?

[geo <gamills@ns.sympatico.ca>]

I'm trouble-shooting lack of diff. lock - and friends, I could have used
them yesterday, came too close to destruction derby for my taste.  I
have checked all vacuum lines and everything seems tight from the bottom
up.  With the diff. lock switch off there seems to be a vacuum leak,
i.e. the sound of air being sucked in, and with the diff. lock switch
engaged this sound disappears but locks do not engage.  I have looked
the switch over carefully but can't really see any problems externally,
and I can't figure out where the 'noise' is coming from.

Query - could it be an internal problem with the switch?  Any help
appreciated as always.

This is my first go at this so I could have missed something, but it
definitely seems to be switch oriented.  BTW, any of you want to give
the ol' quattro a go in snow, slush, ice, freezing rain, you name it,
just take a cruise to Nova Scotia.  We got plenty.

Slip slidin' away......

Geo
5kq without diff locks (and a few other things for that matter, but this
one bubbled up)

Pet peeve - WTH did they make the windshield washer reservoir so small?
Lord Suff'rin' Jeez B'y! (an' that comes after Jeez B'y and Lord Jeez
B'y)