95 S600 ..no air from center vents and no lumbar support - Benzworld.org

Goatman · 06-02-2005, 02:10 PM

I post this separate message to find answers for seperate problems found on my S600.

Testing the vehicle, I found that I have no air coming from the center dash vents. Also my seat support does not inflate on both seats. I assume its a vacuum control problem but I don't know where the vacuum is generated. The central lock works, the backup antennas are working, assume the vacuum pump under the real bench is ok..maybe I am wrong. Does anybody know how the vents and the seat supports are controlled? Any suggestion where to start?

Thanks
Werner.

Peter Guenther · 06-03-2005, 07:34 AM

The lumbars are pressured from the lock pump under rear seat, the pump also provides vacuum when the engine is off. The locks are vacuum to lock pressure to unlock

Goatman · 06-03-2005, 01:30 PM

Quote:

Peter Guenther - 6/4/2005 6:34 PM

The lumbars are pressured from the lock pump under rear seat, the pump also provides vacuum when the engine is off. The locks are vacuum to lock pressure to unlock

Peter, I assumed that the pump is ok, because the locks are working as well as other features driven by the pump. My question is what is controlling the vacuum or pressure. I think that the pump must get a signal from the seat switch (control) to inflate the support, than maybe activate a solenoid to start filling the bladders etc.

Werner

salaburg · 08-10-2005, 11:12 PM

How did you go with this problem as my 400 SEL (1992) has teh same problem. I am told its the vacuum pump under the rear seat that is U/S and that they are also very expensive. Anybody kno of a cheaper fix or an alternative source to buy a new one?

Peter Guenther · 08-11-2005, 07:02 AM

The pump produces vacuum for the HVAC if the engine is off or accelerating, and pressure for the lumbars. The pressure is stored in a reseroir, and the pump runs when neeeded. In addition is produces pressure and vacuum for the locks, back up assist rods, and vacuum headrests if you got them. The pump has both pressure/vacuum safeties in addition to timeout 10 sec in lock/unlock 60 sec in secondary (lumbar and ?).
The pump produces pressure to unlock and vacuum to lock. Faults are supposedly stored and read at test connector with impulse counter!