Educate me on the vacuum system
 

I have a 1994 C280. I tried the search tool but I need some education before I can use what it pulls up.

1. For the last month I've heard what I think is the vacuum pump cycling every 30 seconds or so.
2. Now it is cycling every 10 seconds or so.
3. I have no issues with anything vacuum related (locks, etc) except for controlling the flapper on the center vents for A/C.

Questions:
-- Is this coincidence or does it sound like my vac pump is cycling, I suppose because it is losing vacuum due to a leak somewhere?
-- Why is it affecting one thing but not another?
-- Is the vac pump somewhere in the vicinity of the back seat?
-- What do I do next?

Thanks mucho.

The CL pump is designed to HELP the engine vacuum supply for the A/C system.

You most likely have a vacuum leak in the a/c system & YOU will burn out the CL pump if it runs too much.

FIND & fix (or block off) the leaking vacuum system issue in the a/c system,

Can I access the primary points in the trunk and behind the glove box? If so, what would be the first things to check (and/or color of vac tubes)?

Thanks

The A/C vacuum control valve block is beneath the under dash panel on the passenger side.

Here is a link to the vacuum system http://www.peachparts.com/shopforum/showthread.php?t=89524

Educate me on the vacuum system
 

It sucks.