W140 Vacuum supply line...need help! central locking
 

I have done all of the searches I can think of on this and cannot find an answer. The vacuum pump under the rear seat on my '92 500SEL eventually seized from constant running due to a leak (?). I recently replaced the pump but the leak is still there and I do not want the same failure to recur. The problem is on the clear tubing connected to "PU" on the distribution manifold of the pump, which I understand is the vacuum supply line from the engine. The line itself has a tag on it which is labled "DVS". I traced out the line to where it connects to yet another distribution point under a steel plate in the front passenger footwell. It is #6 on this unit. My question is where does it go from here, and what does it eventually connect to??

I think I can clarify that this is vacuum supplied FROM
the pump to the vacuum distribution block in
the right footwell. (not vacuum from engine)

This will supply vacumm for the A/C flaps to open/close
when engine is not running. (when "Rest" button is pressed)

If one line leak large amount, I would do the induvidual
flap test on the A/C to find out which is leaking, or if the
leak is small, do it on the distribution block.

Flap test (Chart 2);
http://www.continentalimports.com/ser_ic40142.html

br,
syljua

Are you positive about this being for A/C flaps? The reason I ask is that the only time that the pump is active from this clear tubing line is when the transmission is in gear....what would this have to do with the A/C? :confused:

I [I]know[I] that someone out there has to know where this vacuum line terminates...please save me hours of removing who knows how many panels, plates, covers and whatever to find the terminus. Does this go to a module/device in connection to the transmission? The pump activates only when the transmission is put into gear (forward or reverse). I would appreciate any help from whomever!!

Y11 Switchover Valve Unit, 15-connection :
0 Vacuum distribution block
1 Left diverter flap
2 Right diverter flap
3 Left blend air flap
4 Right blend air flap
5 Side air outlet diverter flap
6 Left defroster flap, long stroke
7 Left defroster flap, short stroke
8 Right defroster flap, long stroke
9 Right defroster flap, short stroke
10 Main air flap, short stroke
11 Main air flap, short stroke
12 Left footwell flap, long stroke
13 Left footwell flap, short stroke
14 Right footwell flap, short stroke
15 Right footwell flap, long stroke

Air Conditioner Unit :
1 ACC vacuum storage reservoir
2 Connection for ACC vacuum storage reservoir
36 Vacuum distribution block
37 Vacuum element, left defroster flap
38 Vacuum element, right defroster flap
39 Vacuum element, diverter flap, left side air outlet
40 Vacuum element, diverter flap, right side air outlet
41 Vacuum element, diverter flap, left center air outlet
42 Vacuum element, diverter flap, right center air outlet
43 Vacuum element main air flap, rear
44 Vacuum element, main air flap, front
45 Vacuum element, blend air flap, left center air outlet
46 Vacuum element, blend air flap, right center air outlet
47 Vacuum element, left footwell flap
48 Vacuum element, right footwell flap
49 Vacuum element, air recirculation flap

Color Code :


bl = blue
hbl = light blue
drt = dark red
ge = yellow
mgn = medium green
gr = grey
rt = red
ws = white
sw = black
dgn = dark green
gn = green

Connection Diagram - Vacuum Valve Block


No . Color From/To
1 medium green/yellow Footwell air conditioner
2 light blue Seat backrest lock
3 violet Headlamp range adjustment switch (input)
4 violet-yellow Headlamp range adjustment element (left)
5 grey-green Valve block (Y11)
6 white (transparent) Intake manifold vacuum assist
7 grey Intake manifold vacuum
8 Connection not assigned
9 violet-yellow Headlamp range adjustment switch (output)
10 violet-yellow Headlamp range adjustment element (right)
11 black-grey 2nd selection program automatic transmission (system)
12 black-grey 2nd selection program automatic transmission (reservoir)
13 red-grey Air conditioner reservoir

The vacuum from this pump provides back up vacuum from the engine. This allows the HVAC to work without the engine running (like res. heat) or when accelerating. You dont want your systm to change when you accelerate (no vacuum)
There is probably a check valve since there is a vacum reservoir up under the dash (i think) that probably feeds the distribution block. The picture book shows it but does not say where it is, but looks like front

Wow, thanks guys for all of your time! From the diagram my problem lies in the intake manifold vacuum assist (#6 on the vacuum valve block). Now, I just need to find this, which I assume is on the upper engine somewhere. Wish me luck.

The pump runs to extend/retract the backup rods on
the back fenders when a switch to/from reverse is made.
This is on the red line? I do not have them, so not sure.

Try pressing "Rest" after engine turned off, and see it the leaky
line is active then.

br,
syljua

Syljua.....the parking assist rods function perfectly from this same pump, but they are on the red lines. When the transmission is put into any gear the pump begins to run, and it runs continuously until about 10 seconds after it is put into either neutral or park, and it is the clear tubing on "PU" that either isn't holding vacuum or pressure.