Diff lock help

[Dingo]

After emerging from its winter sleep the diff lock switch is behaving differently, when I press the button it locks and un locks the diff as it should and the little yellow triangle goes on and off, but the green light on the switch and the ABS light on the dash doesn't come on anymore, before I randomly pull things apart could anyone tell me what I should be checking
Oh its a late ABY coupe, Thanks

[Henkjan]

iirc: the green light goes on (and abs goes off) only if the switch on the diff says it's actually locked. so either the diff is locked and the switch does not give that signal, or the diff does not lock properly; the latter could be caused by a leaky vacuum tube/hose

[Dingo]

The diff is definitely locking / un locking, so must be switch on diff, will investigate soon as
Many Thanks

[Monkeymagic]

The bulbs LEDs can go pop. I have just been working through a few on mine that have stopped working after the winter storage

[UrS4boy]

Diff Lock 101

Have a read on this:

Diff Lock 101: Rear Differential Lock Controls, the whys/hows for the 92-94 UrS4, 95 UrS6, S2 and RS2

http://forums.quattroworld.com/s4s6/msgs/170940.phtml