Recently I got stuck in snow and really needed my differential lock to work.

Here's the situation. I press the differential lock and nothing happens. No lights come on. ABS does not get disabled. No clicking, just nothing. Doesn't work running nor at a standstill. I know a couple of the lights are burned out, but i witnessed it not working when we got stuck in snow. Hopefully this is a common problem and someone has some experience they can share. Any ideas?

--Kyle

 

check the vacum lines

 

Jack up the car hook up a handheld vacuum pump and see if the actuator is working. According to my Audi books it is a common problem for the rubber bellows to rupture.