color coded vacume box behind w124 glove box
 

I know it controls the differnt a/c vents I dont know what its called but all but one hole is blocked. Is this normal?

some one please help me

When you write . . .
 

that one port is blocked, are you referring to one nipple/port having a cap over it? If so, I believe mine ('87 300TD) did. Though I do not remember the procedure exactly, I think what I was instructed to do was apply vac to each port checking for leakage. Somewhere in my cranial cavity I seem to remember a warning about not getting too carried away with the amount of vac though I am possibly getting two routines mixed up. Larry Bible was the source for my testing procedure . . .

What are you attempting to accomplish/solve?
Steve

Not counting the top of the switchover valve (Y7), the ports are numbered top-to-bottom, 1>7 (Y1-Y7). Per manual that would be Y1 dark red to elements for fresh/recirculated air flaps, Y2 medium green and light blue to same as Y1 (only one of the elements though) as well as vacuum reservoir except on diesels, Y3 red and yellow to elements in the footwell, Y4 red and black to element of the center nozzle flap, Y5 red and white to defroster, Y6 medium green to diverter air flap, and Y7 red and light blue to defroster. As you can see, I was probably incorrect in thinking mine had a cap on one port (unless Y2 since mine is a diesel). If yours has the lines or ports plugged/capped then there may be leaking accumulators (elements above) and a PO chose to have fewer vacuum leaks. Can you get air flow from any of the vent outlets? Do you have a miti-vac? If yes to the latter, you can check the accumulators/elements as well as test the switchover valve. Do some searches for the precautions. The "Service Manual Automatic Climate Control Model 124" from MB of North America, Inc. is an excellent soft cover book to own . . .
Steve