The driver's seat lumbar inflator was not working in my 2003 986 Boxster. The switch worked fine and the inflator motor was running but nothing happens in the seat.
The inflator pump is located in the right seat bolster. It can be exposed by 1) pulling the seat center section up from the bottom then pulling the top up to unclip it.
Then by pulling the leather loose from several clips you'll see the pump. It is 4.5 inches long by 2 inches at the widest. Two wires are connected to the bottom and
the motor can be removed from the foam surrounding it by pulling up, exposing the wiring connection - red and white. The air hose goes to some sort of regulator or distributor in the
headrest - I don't understand what it does though.
The seat can be removed with 4 male torx bolts - E12 socket. Disconnect the battery ground before disconnecting the wiring underneath as some say if you don't the air bag warning will come on. I got the seat unbolted and disconnected
the large wiring connection underneath but upon lifting found a large control box fastened under the seat where there was no easy way to further disconnect the wiring (seat heat, memory, lumbar). Maybe simpler seat controls or
earlier models don't have this problem. So I left the seat loosened but int he car. Good time to do some vacuuming.
I opened up the valve section of the air pump and found the little opposing pistons working without any obvious tears but it still not pumping air.
The Porsche part (99662072500) is rather expensive and apparently unique to Porsche, but I found a NOS Ford air pump, E6DF-2875 that was very inexpensive. In fact I believe almost any OEM pump from the era where air was
used to inflate bladders would work fine. The Ford pump was larger and I had some trouble getting it to fit in but it worked, even the air hose connection is
the same diameter.