more 4kq diff lock probs...

[rjandrew@post.cis.smu.edu (R Justin Andrews)]

Hell everyone ...
I hate troubling everyone with questions but I have just run 
across something that I've not seen mentioned here.... I have 
an '86 4kq with the vacuum actuated diff locks well, the locks
perform properly it's just that the center light does not come
on when locked (even though the diff does lock) and it flickers 
when unlocked while driving down the road... 
Please... someone giv me an idea.... Vacuum check valve?
Solenoid if it has one? leaky diaphram???

Thanks much!
Rich Andrews
rjandrew@post.cis.smu.edu