4kq differential locks ?s

[Ryan Moon]

I'm curious about the diff locks. They are activated by vacuum, but is 
it possible for them to stick or stay locked ?
Is the front lock mechanism is on top on the transaxle towards the 
passenger side, where you'd have to remove some of the exhaust to get 
to it ?
The lights on the switch panel in the passenger compartment are 
activated by switches similar to reverse light switches ? So meaning 
the light would only come on if the diff is locked? Or the light would 
stay on if the diff doesn't unlock?

Thanks
Ryan Moon