The vacuum pump in the rear (in the trunk) controls the central locking and all the vacuum pods of the heater system. Depending on the fact whether you have a passengerís airbag and what the exact leak of your recirculation system is, you can access the valve itself through the glove compartment.
There is a lock in the glove compartment box, can you control it or not, does it make any difference in opening it or not? If anything inside the lid did snap, you will need a new innerhalf of the lid (no repair possible and costs involved 60 dutch guilder --> 20 US$). You might want to consider to break the handle or the outer skin (approx. 100 dutch guilder --> 45 US$) to get access again.
Removing and replacing the dash of a C class can be done in 3/4 of a day (6 hours) by one person only. I would be very glad if I was to do the repair for 1500 US$...it would even be worth to buy the return plane ticket for. TOO EXPENSIVE!
with a minor 600+k