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1994 SL 320, 1996 S-Class
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18 Posts
Discussion Starter · #1 ·
My interior storage compartments have locked and won't open. Is it vacum or pressure to unlock them. Can I used my mity vac to put vacum or pressure on vacum line coming out of the pump to get them unlocked?? How do I identify which vacum line it is?? Thanks! 1994 SL320
 

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Departed 1998 SL500 (and the Pano is in Bogota)
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13,315 Posts

· Registered
1994 SL 320, 1996 S-Class
Joined
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18 Posts
Discussion Starter · #4 ·
Does the system send both vacum and pressure thru a single vacum hose? So if vacum locked my storage compartments then if I put pressure on the same line it will switch the actuator to unlock??? Thanks!
 

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1994 SL 320, 1996 S-Class
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18 Posts
Discussion Starter · #6 ·
Thank you. I put air pressure on the line and got my compartments open. I don't think I am getting any vacum out of my pump. When I take the fittings off of the top of it, and turn the key in the trunk lock, right and left, I only get pressure when I turn left, nothing when I turn right. I can only lock my car manually. Is the pump repairable to get vacum to work? This pump is only 8 months old. My old pump burned up and quit working.
 

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2005 SLK350, 91 300SL with Pano Top, 04 S500, 2015 Tesla Model S
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2,205 Posts
If the pump generates pressure, it is working. It switches between sucking and blowing by reverse voltage applied. The culprit might be that your big connector on the control unit is not seated all the way. Unplug it and replug it.
 

· Registered
1994 SL 320, 1996 S-Class
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18 Posts
Discussion Starter · #8 ·
I tried unplugging the pump and plugging it back a bunch and no luck. I still only have pressure, no vacum. When I turn the key in the trunk lock to unlock the pressure comes on, when I turn to lock, nothing happens. I get the same reaction at the door locks. The red and green lights work as they should, but the pump won't suck, only blow.

What other causes for this could there be? Pump only makes pressure, no vacum. Would there be a fuse going to the pump that only effected the vacum function?

Thank you!!!!!
 

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2005 SLK350, 91 300SL with Pano Top, 04 S500, 2015 Tesla Model S
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2,205 Posts
I tried unplugging the pump and plugging it back a bunch and no luck. I still only have pressure, no vacum. When I turn the key in the trunk lock to unlock the pressure comes on, when I turn to lock, nothing happens. I get the same reaction at the door locks. The red and green lights work as they should, but the pump won't suck, only blow.

What other causes for this could there be? Pump only makes pressure, no vacum. Would there be a fuse going to the pump that only effected the vacum function?

Thank you!!!!!
Unplugging the pump is not what I meant. I meant the control unit connector. This is mounted on the frame support in the trunk.
 

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· Registered
2005 SLK350, 91 300SL with Pano Top, 04 S500, 2015 Tesla Model S
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2,205 Posts
Another thought. If you can hear the pump running when it is supposed to suck, then a small rubber pipe inside the pump housing has disconnected. take the pump apart and investigate. Make sure you label all the air pipes as to position before pulling them off or you will have a hell of a time trying to figure out which one goes where. Don't ask how I know.
 

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1994 SL 320, 1996 S-Class
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18 Posts
Discussion Starter · #12 ·
I took the connector off of the module and I thought we had found the problem. There was some corrosion. I sprayed it down with WD-40 and used a toothbrush to clean it up. I put it back together thinking it would be fixed, but no change.
The pump only makes noise when you turn the key to unlock and it is blowing. It seems like for some reason it either isn't being told to reverse or it is unable to reverse and create vacum.
Thanks for the help!!!
 

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2005 SLK350, 91 300SL with Pano Top, 04 S500, 2015 Tesla Model S
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2,205 Posts
That corrosion might be it. WD40 is not the stuff to use. Get some electrical contact cleaner from Radio Shack. Spray on the connector and into the socket. Then plug and unplug this connector several times to clean the contacts.
 
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