Locking the diff on 4kcsq

[Robert_Manger@mastercard.com]

I finally have the handy Bently to check out my switch and locking the diff.  I
took the dash apart last night and noticed that the white line from the engine
compartment has not pressure or sound for that matter at all.  I looked for the
vac hose from the origin and found it frayed so I replaced it and that had no
effect.  What is the purpose of the check valves could they be bad since I get
no pressure within the car?

Help I want to get this thing working before the winter comes, yes I am a little
early, but it tends to creep up fast.

TIA

Rob