I also have problems with this pump.
I see that the P+ pressure connection is divided into 3 pipes.

Look at this picture (blurry cellphone image taken in my 1997 S320)



I think I have read somewhere that;

The yellow ones are for ZV and boot.
The single white is vacuum from engine.
The black are vacuum back to HVAC.
The double white are for read headrest?
The disconnected pipe (not shown) are the grey one beeing divided into 3 grey ones on the left for the lumbar.

Why 3 for lumbar? (there are only 2 seats?) Am I loosing something else
here?

How does the rotaty dial on the seat regulate the pressure on
the lumbar support?

My pump does not give pressure on this connection at all. Even
after disconnecting it for a while. But all the other functionallity works
like ZV, HVAC and rear head rests down.

br,
syljua