There are two pumps in the car, the one under the passenger rear seat handles lock/unlock, lumbars, backup assist, trunk handle, provides vacuum for HVAC when car is not running, lumbars, and rear headrest with the non electric rear seat. It is a failed pump $spensive, a leak in the system it shuts off in 10 seconds on the locking function and it shuts off in 60 seconds on lumbar and climate control leaks.
If the doors and trunk dont pull down it is the other pump over the drivers side rear wheel also $spensive.
There is a release uner the trunk lid that allows the latch to be retracted manually it is in the owners manual.
I think there was a bulletin about a defective hose in the pump but I seem to recall it was for a later model. I would pull the fuse wait and reeinstall it to see if you can hear the pump run, there is also a tool called MIGHTYVAC which can be used to draw a vacuum in the various circuits (hoses) to see if they hold.
The close assist also has a safety, two attemts and it will disable the circuit.

Thanks.
Heres my situation.

Of course, as most of W140's, my close door assist works for at least two times to like days(when its cold).
But that worked until two days ago and the close assist still works at the doors.
I checked the fuse #3 at its fine.
When I press the button that opens the trunk (after previously manually pressing the lock inside) you can hear the sound things moving(so I guess the pump is ok) where the latch is, but the latch doesn't come out.

I hope this helps.

check fuses in trunk I believe #9 is for closing assist and the backup antennas are probably on a different fuse. Even if the fuse is not blown remove it and wait a couple of minutes to allow for reset and then reinstall fuse and see if things work.
Hope this helps

i know this is an old post, but hey... its related.

anyway, we have acquired a 95 s280. everything vacuum works except for the backup antennas. how is it triggered? i'm willing to cut up some wires to test trigger the pump if ever. thanks guys

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85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project

I'm having similar problems with my 93 300SE. Although my closing assist system works, my locks, back-up assist antennas, trunk handle and lumbar quit working.(the lumbar has been out for months, the others just went out last week)

did they stop working all at the same time?

anyone?

__________________

85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project

My lumbar have been out for a while. I suspect there was a leak in tha passenger side seat. But all the other systems just went out the other night.

Its not "normal" for the closing assist not to work. My 99's closing assist works flawlessly every time. Take a look at the URL that was posted earlier. You may need to invest in a new closing pump or may have some leaks in your vacuum system. Im dealing with a vacuum leak myself in my 126.

Sometimes you can extend the life of the pump by a couple of years by disassembling the pump and cleaning the orange disk valve and seat that is in the end of the pump.
As the pump wears, graphite powder builds up on the seat of the valve reducing the pressure that the pump can produce.
Place a mark across the sections of the pump so they can be properly re-assembled. Remove 5 screws holding the end of the pump to the electric motor. Disassemble.
You will notice bumps of graphite on the seat. Clean the seat with a Qtip and water (maybe little soap), clean the disk and screen.
Re-assemble and evenly tighten the 5 screws.
The above is for the Bosch pump.