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1998 S280
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Discussion Starter · #1 ·
I notice my W140 has vacuum pump central locking, and i was curious... is there any advantage to that over a standard motorised system, or is it just an older technology?

Thanks.
 

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92 500SEL to 01 E320T current 2014 lexus LS460
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Locking

The system on the 140 is not much different than the previous, except it is integrated with keyless entry.The old system used a pump to lock and unlock controlled by a switch in the drivers door. The new uses an IR signal from either door or trunk to lock or unlock everything. The pump also provides output to the AC system, seat bolsters, vacum headrests, and backup guide rods. The newer motorized system of course uses wires and motors to do the same thing, diaphrams and hoses sometimes leaked, of course motors go bad also
 

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1994 W124 E320 1997W140 S320(RIP),1993W140300SE(RIP),2000W208CLK320(RIP) , 1993 W201 190E 2.6 (RIP),
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Fixed my vacuum pump, but...

Good info, boys. However, it doesn't answer why my locks and rear head rests still don't work after I fixed the vacuum pump. What should be my next step? Fuses? And yes, I DO need to replace my IR key. Just using regular spares right now. Thanks for answers in advance. THis board is great.
 

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92 500SEL to 01 E320T current 2014 lexus LS460
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locking pump

What did you fix on your locking pump, does the pump run. If it does, it should activate some thing. If the pump does not run, it wont operate your lumbar, headrests if you got vacum ones, or HVAC support.
 

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1994 W124 E320 1997W140 S320(RIP),1993W140300SE(RIP),2000W208CLK320(RIP) , 1993 W201 190E 2.6 (RIP),
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Re: locking pump

What did you fix on your locking pump, does the pump run. If it does, it should activate some thing. If the pump does not run, it wont operate your lumbar, headrests if you got vacum ones, or HVAC support.
Dtkw, you say could be switch. Could you breifly tell me how to check it? Sorry for being a dumbo on this.

Next, Peter, you specified LOCKING pump. THe vacuum pump I pulled was in the trunk on the drivers side. Pulled it out and gave the "tuning" screw a half turn. Reinstalled. Wal-lah! Fixed. Are we talking about the same pump? If not, please inform. Thanks MUCH!
 

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92 500SEL to 01 E320T current 2014 lexus LS460
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Vacum Pumps

The 140 series of cars had two pumps. The one over the rear wheel "CLOSED" the doors and trunk lid. This means it pulled them in after the first catch is noticed by the pump computer. I was a little leery about the screw trick, but it seems to be working for some people. I had a second go bad and MB replaced it at N/C after almost a year, never attempted to fix the first.
The second is a locking and unlocking pump, this pump is located under the passenger rear seat in a foam enclosure. This pump provides vacum/pressure to lock and unlock the doors, trunk, gas door,lumbar, HVAC assist, rear headrests if you dont have electric seats, and the trunk handle on some cars (there was a mod to use the closing pump for this). If the handle and lid go in at the same time, you have the mod, if they seemm to be independent (delay) you dont. This pump runs forward and backward to lock and unlock the doors, and gets its input from the keys in the front doors and trunk, the switch in the inside, and also from the "remotes". Those pumps dont go bad as often.
That should help you a little
 

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1994 W124 E320 1997W140 S320(RIP),1993W140300SE(RIP),2000W208CLK320(RIP) , 1993 W201 190E 2.6 (RIP),
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Re: Vacum Pumps

The 140 series of cars had two pumps. The one over the rear wheel "CLOSED" the doors and trunk lid. This means it pulled them in after the first catch is noticed by the pump computer. I was a little leery about the screw trick, but it seems to be working for some people. I had a second go bad and MB replaced it at N/C after almost a year, never attempted to fix the first.
The second is a locking and unlocking pump, this pump is located under the passenger rear seat in a foam enclosure. This pump provides vacum/pressure to lock and unlock the doors, trunk, gas door,lumbar, HVAC assist, rear headrests if you dont have electric seats, and the trunk handle on some cars (there was a mod to use the closing pump for this). If the handle and lid go in at the same time, you have the mod, if they seemm to be independent (delay) you dont. This pump runs forward and backward to lock and unlock the doors, and gets its input from the keys in the front doors and trunk, the switch in the inside, and also from the "remotes". Those pumps dont go bad as often.
That should help you a little
Help a LITTLE?? Whoa! That was dead on! Thanks Peter! I take it I'll have to pull the rear seat on this one? Is there a "screw trick" to this one, as well? (please let there be:)
 

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1994 W124 E320 1997W140 S320(RIP),1993W140300SE(RIP),2000W208CLK320(RIP) , 1993 W201 190E 2.6 (RIP),
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Well, I pulled it, but alas

No luck this time. I did find two tuning valves and tried it twice, turning two ways, but it sounds like the pump is not running. I'm not hearing anything from it. Is there a fuse I should try before I ONE DAY, (not now), go this http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33610&item=2431156251 route?
 

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92 500SEL to 01 E320T current 2014 lexus LS460
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Lock Pump

If you got it out play with it, I am not up on that pump, but it is supposed to develop pressure and to develop vacum, to lock and unlock it also has a valve that shuts it off if the pressure gets to high, and another if it cant develop ample vacum. you should get it to run, or see if there is power to the motor. I dont know what fuses control it, but the fuse boxes could be some help, dont assume the fuse is good because it looks good there are little checkers that you put across it and a little "led" comes on.
I dont know why this guy wants you to bid on the pumps,when I need it I want it, check around. I do know the pump has been replaced by MB and the replacement comes with fittings and hoses and a adpter plate.
ZV Connection for lock & unlock YELLOW hose
RH Connection for backup asist rods ORANGE
SFG Connection for trunk lid grip BLACK
FKS Connection for headrests (non power rear seats)
P+ Connection for orthopedic GRAY
P- Connection for manifold vacum HVAC CLEAR
 

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1994 W124 E320 1997W140 S320(RIP),1993W140300SE(RIP),2000W208CLK320(RIP) , 1993 W201 190E 2.6 (RIP),
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Thanks much

I'll play with it some more and check the fuses before I pay anything. I discovered that pump on my own on Ebay. It's nice to know it's there if I have to go there.
 

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2010 E350 P1/P2, 2008 S550 Designo, 2002 ML320
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RE: Lock Pump

Peter Guenther - 9/6/2003 1:42 PM

ZV Connection for lock & unlock YELLOW hose
RH Connection for backup asist rods ORANGE
SFG Connection for trunk lid grip BLACK
FKS Connection for headrests (non power rear seats)
P+ Connection for orthopedic GRAY
P- Connection for manifold vacum HVAC CLEAR
Holy Crap! You just saved my bacon sir! Do you know how hard it is to come by this information? I stupidly removed my pump to avoid a core charge and completely forgot where the lines went.

I've got cold Cerveza and the best damn burrito you will ever eat if you happen by Phoenix sometime.

Cheers!
 

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this thread is awesome.

Also, does anyone know what the smaller plug on the vacuum pump under the rear seat is for? Someone hacked up my wiring harness. I got the main plug wired back up fine, but the small one that plugs into the pump right next to the large one still has wires leading to nowhere.

I cannot even find a reference to it in alldata. I see the connector, but i can't find the wiring diagram for it.

This concerns me because my side vents don't work, and i think it may be because those wires aren't hooked to anything.

Thanks
 

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Does anyone know what the TBS lines are for? On the manifold (for the pre-facelift pump), there are four would-be cut-outs for TBS...

And, can someone tell me what exactly the pump does for the HVAC system?

Thanks.
Are there any hoses attached? I see the ports in AllData, but there's no mention of anything hooked to them.

As for the HVAC part - it's used for two purposes (and it's called MVA - Manifold Vacuum Assist) - 1) while the car is running, it makes sure that under all conditions, there is sufficient vacuum to activate the various dampers in the A/C system, regardless of engine load. 2) with the car off, and the HVAC control set to Rest, the pump again provides vacuum to move the HVAC dampers.
 

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this thread is awesome.

Also, does anyone know what the smaller plug on the vacuum pump under the rear seat is for? Someone hacked up my wiring harness. I got the main plug wired back up fine, but the small one that plugs into the pump right next to the large one still has wires leading to nowhere.

I cannot even find a reference to it in alldata. I see the connector, but i can't find the wiring diagram for it.

This concerns me because my side vents don't work, and i think it may be because those wires aren't hooked to anything.

Thanks
I think the extra plug you're talking about is the interface connector for the anti-theft/alarm module (N26), plus one wire to the HVAC controller.

NOTE - these values are for a '93 300SEL - your wiring harness may be different
I found the pinout in Vehicle / Diagrams / Electrical Diagrams / Antitheft and Alarm Systems. This is what I found:
Pin 6 - Blue - N26 Pin 11
Pin 4 - Blue/Gray - N26 Pin 19
Pin 5 - White/Pink - N26 Pin 24
Pin 3 - Brown/Green - N26 Pin 26
Pin 2 - Brown/Pink - N26 Pin 25

Before I'd reconnect any of these wires, I'd pull the connector from N26, which is in the trunk and is the only non-rectangular module mounted to the upper right of the fusebox. Test connectivity from the pins back to your open wires before making any repairs.

I'm afraid this has nothing to do with your side vents.

Silly question, but you do have the valves open for the vents (the outer pair of dials below the center vent), right? If they don't work at all, I'd suspect the multiplexer device behind the glove box. Everything HVAC is controlled from that device which is controlled itself by the main HVAC control in the dash.

There is a flapper test program for the HVAC to help you diagnose problems just like these: Vehicle / Heating and Air Conditioning / Testing and Inspection / Component Tests and General Diagonstics / Component Tests / Individual Flap Test in AllData gives you the procedures. It should point you to where the problem is preventing the side vents from opening up...

Good luck.
 

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1997 S500. Black on Black
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I think the extra plug you're talking about is the interface connector for the anti-theft/alarm module (N26), plus one wire to the HVAC controller.

NOTE - these values are for a '93 300SEL - your wiring harness may be different
I found the pinout in Vehicle / Diagrams / Electrical Diagrams / Antitheft and Alarm Systems. This is what I found:
Pin 6 - Blue - N26 Pin 11
Pin 4 - Blue/Gray - N26 Pin 19
Pin 5 - White/Pink - N26 Pin 24
Pin 3 - Brown/Green - N26 Pin 26
Pin 2 - Brown/Pink - N26 Pin 25

Before I'd reconnect any of these wires, I'd pull the connector from N26, which is in the trunk and is the only non-rectangular module mounted to the upper right of the fusebox. Test connectivity from the pins back to your open wires before making any repairs.

I'm afraid this has nothing to do with your side vents.

Silly question, but you do have the valves open for the vents (the outer pair of dials below the center vent), right? If they don't work at all, I'd suspect the multiplexer device behind the glove box. Everything HVAC is controlled from that device which is controlled itself by the main HVAC control in the dash.

There is a flapper test program for the HVAC to help you diagnose problems just like these: Vehicle / Heating and Air Conditioning / Testing and Inspection / Component Tests and General Diagonstics / Component Tests / Individual Flap Test in AllData gives you the procedures. It should point you to where the problem is preventing the side vents from opening up...

Good luck.
Thank you for your help. I'll do the test when i get back to the shop.
 

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Regarding the pump let me add ,I just had mine go bad a new one is $950 at hte dealer $350.00 on the Net.
Mostly it's the motor, Eddie gave me the advice he also he send me a working motor for $45.OO and Bingo everything works again.
To change the motor takes 10 Minutes or less.
If you are in need for used parts from an honest guy with fair prices here is his E-mail [email protected]

ulf
 

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1994 S500 Sedan
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Brian, Nope, nothing is attached to TBS - strange. I wonder what it could be for!? Seems to be a mystery thus far. Otherwise, thank you for the info on the pump's funcation as support for the HVAC system.
 
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