Just fixed by 96 c280 rear head rest. It was vacuum leak at the vacuum block under the hood, passenger side under the cover. Make sure all the lines are connected and all ports on the vacuum block have a line attached or a plug inserted. You can also test this in the trunk. locate the vacuum line feed under the rear deck at the headrest and pull a vacuum on the line with a hand vacuum pump and try the dash button (electric) with the ignition key in the on position. You can also pull a vacuum from the block location. The rear headrest is a off white color no. 6 / ? position

 

wilbur, Can you help me out with something? I've asked several times on here for a vacuum distribution block diagram and no one has helped me out. Like I've already stated, I fixed my rear headrests too, but on the distribution block, I have one empty "socket" and it doesn't have a plug in it either. I'm just curious if you know what line is connected to yours/ or where the line feeds? When standing next to the car looking at the block, it's the socket all the way to the left and on top (above the rear headrest line).

Thanks
tim

 

Tim,
If you look close at the block it is numbered at each location. I have not been able to obtain a layout of the block either. I am quiet sure the block is nothing more than a distrubution block being just a junction block that is empty on the inside. I have seen vacuum distribution headers in place of the block type. I solved my vacuum problems by putting a mercedes plug in an empty port I found. I assumed the plug removed itself. I belive the dark green line with a white stripe is the main vacuum line that puts vacuum on the block and other lines thus are served from the block. I could not obtain vacuum until the empty location was plugged. mercedes part no. 202-805-03-44 / vacuum plug $4.50 (looks like 10 cents worth) Be careful, the lines and connections are very brittle
hope this helps

 

Thanks a ton. Now that I have a part # I'll go to the dealership.
Tim