PSE pump - Humming noise-Is it Normal?
Thread Starter
Junior Member
Joined: Apr 2012
Posts: 41
Likes: 0
From: New Orleans , LA.
ML 320 HEAVY METAL EDITION
PSE pump - Humming noise-Is it Normal?
99 E320. PSE pump under backseat is making noises. humming , pumping after start up. Is this normal? Should I be concerned? All locks and windows work perfectly.. Although I did notice the cruise shut off a few times the other day 
Thread Starter
Junior Member
Joined: Apr 2012
Posts: 41
Likes: 0
From: New Orleans , LA.
ML 320 HEAVY METAL EDITION
it's definitely the pse pump. ( enclosed by foam under the seat. )
touched it while it was making the noise. so verified.
All lines are attached well. Just curious if it was normal... All locks are working fine.. not sure what all this pump runs to though. Still learning all I can about 1st MB.
Did notice the battery was wet, and in the batt compartment was wet on bottom as well. Little concerned about this because the fuse box & pse pump are located here too. If its battery acid or fluids, would hate for it to damage any of these. (Keeping a eye on it.)
ALSO - does this pse have anything to do with stiff riding in rear? such as hard bounce over bumps (air ride or such?)
touched it while it was making the noise. so verified.
All lines are attached well. Just curious if it was normal... All locks are working fine.. not sure what all this pump runs to though. Still learning all I can about 1st MB.
Did notice the battery was wet, and in the batt compartment was wet on bottom as well. Little concerned about this because the fuse box & pse pump are located here too. If its battery acid or fluids, would hate for it to damage any of these. (Keeping a eye on it.)
ALSO - does this pse have anything to do with stiff riding in rear? such as hard bounce over bumps (air ride or such?)
Thread Starter
Junior Member
Joined: Apr 2012
Posts: 41
Likes: 0
From: New Orleans , LA.
ML 320 HEAVY METAL EDITION
Plutoe.. I do my homework before I post new threads so..The manual has been read back to front and sideways. Not seeing anything specific.
Of course... since they dont want you to work on your own vehicle, this is where the MB service comes in to jack up those $$ on parts labor - Unlike any other vehicle, MB has alot of features that I am slowly learning about thanks to people like you & in the forum. Unlike some out there, I'm not afraid to get dirty to fix my own car, and all I learn here is appreciated.
Of course... since they dont want you to work on your own vehicle, this is where the MB service comes in to jack up those $$ on parts labor - Unlike any other vehicle, MB has alot of features that I am slowly learning about thanks to people like you & in the forum. Unlike some out there, I'm not afraid to get dirty to fix my own car, and all I learn here is appreciated.
MBWorld Fanatic!
Joined: Mar 2006
Posts: 1,627
Likes: 5
From: West Virginia
2001 E320 RWD - Brilliant Silver/Ash: 100,000+
I would try to find the source of water in the battery area. As you noted, there is a fuse box there and if gotten wet that can cause all sorts of weird electrical things.
