Vacuum Lock on C36 - Please help
 

I recently had a shop install a Viper keyless entry on my 1995 C36. Everything was working great for 2 days until my door locks quit working. I took it back to the shop and they looked at my car for 2 hours and then showed me that the problem was coming from the vacuum pump in the rear. They said they tested the system by blowing into the hoses to make sure that there was no leak. So they told me to get the vacuum pump fixed and then take it back to them to re-connect the keyless entry system. Before I take my car to my mechanic, does their diagnosis sound correct? It seems a bit strange that my vacuum pump has been working great for years and all of a sudden fails 2 days after the addition of a keyless entry. Any advice?
Thanks.

This does sound a little strange...I would take to an independent Mercedes shop to get an opinion on this.