locking pump operation question - PeachParts Mercedes-Benz Forum

locry · #1 12-26-2009, 12:26 AM

... what triggers the pump to lock/unlock? and what tells it to stop?
car is an 87 300TD

i'm in the process of installing a remote, i want to eliminate the connection to the door/hatch to the pump, and rely instead on the remote system and the pump alone.

all i THINK i know is the pump either pumps/sucks depending on a signal positive/ground which is supplied to any 1 of the 3 prongs in the round connector at the pump.

as of now i can supply both positive and negative signals to the 3 prong plug via 2 single throw relays... is that all that's needed? (don't have double throw relays at the moment)

i bench tested the pump by applying a signal less than a sec(not sure if positive or ground) to one of the 3 prongs and the pump ran as it should... only thing is... it kept running, i had to disconnect the rectangular plug to stop the pump. the vac line was disconnected when i did this...

so... MAIN question really is... what tells the pump to stop running? an opposite signal? or is there an internal pressure switch? (hoping there is... makes things much simpler)

thanks guys

btw, read all about the crutchfield type installs... doesn't apply to me as i'm going to be installing direct to the pump and removing all connections to the doors/hatch

locry · #2 12-26-2009, 02:52 AM

done!!!

i'll answer my own question for future reference... the pump indeed has a pressure shut-off switch...(it'll stop once the actuators have done their jobs, assuming no major leaks are present) all the pump requires to run is a positive/negative signal to one of the 3 prongs... positive=unlock, negative=lock

i used 2 single throw relays to supply positive/negative signals... the relays are energized by the alarm control unit's LOCK/UNLOCK leads...

all POSITIVE/GROUND requirements i just spliced from the pump's rectangular connector... in my case, it only had 2 wires, positive/negative.

my locks are now actuated via the remote ONLY. makes troubleshooting in the future a whole lot simpler.

for now i just utilized the lock/unlock functions... i have yet to wire the siren, door open/close signal, ACC connection...

right now the car locks itself 15secs after unlocking... which is somewhat irritating... hehe...

sooooo... where is the nearest ACC line? it's a 300TD 124 btw... pumpo and comtrol unit is under the rear passenger seat also.

ah-kay · #3 12-26-2009, 03:49 AM

Quote:

Originally Posted by locry

right now the car locks itself 15secs after unlocking... which is somewhat irritating... hehe...

Wire the door open trigger ( does not matter + or - ) to the parking light wire. This light coming on and off will simulate the door has been opened. It saves a lot of hassle to wire it to the 'real' door trigger. I did it with all my remote.

locry · #4 12-26-2009, 06:27 AM

Quote:

Originally Posted by ah-kay

Wire the door open trigger ( does not matter + or - ) to the parking light wire. This light coming on and off will simulate the door has been opened. It saves a lot of hassle to wire it to the 'real' door trigger. I did it with all my remote.

ey thanks for the tip! parking light? or convenience light? the ones on the headliner? if so i may have to wire both front and rear... coz the front and rear lights in my car are separate.

how are the door triggers wired anyway? if i do wire it to the door plunger... will it work if i open a different door?

ah-kay · #5 12-26-2009, 01:59 PM

Quote:

Originally Posted by locry

ey thanks for the tip! parking light? or convenience light? the ones on the headliner? if so i may have to wire both front and rear... coz the front and rear lights in my car are separate.

how are the door triggers wired anyway? if i do wire it to the door plunger... will it work if i open a different door?

I do not mean the real parking light. I meant to tie the control lines, parking light control and door trigger, from the box TOGETHER.

The parking light control lines will go to 12v 2/3 times when you lock or unlock. If you tie it to the door tirgger then the computer would think you have opened the door 2/3 times and would not lock the car automatically. It is so easy. You can connect to the real driver's door if you wanted to but it is a lot hassle.

Hope this help.

locry · #6 12-29-2009, 08:12 AM

now i get it!!! that's brilliant bro! thanks again.

locry · #7 01-04-2010, 07:13 AM

update... tying the lines together didn't work for me. I'm not sure if the computerbox required a different polarity or the pulse was too quick...
anyhow, i just wired the trigger to a rear door trigger. I have yet to wire it to the front.

Phil · #8 01-04-2010, 02:48 PM

Look at post # 13 on the attached.
Door locks 1982 300SD W126

If your system is the same as it is on an 83 then this will help.There is a diaphragm and lever inside the pump that switches from pressure to vac and back and shuts off the pump when the pressure or vac reaches its max.

locry · #9 01-04-2010, 09:01 PM

ey thanks for the link Phil.

i've pretty much solved my vac pump issues.

my latest concern was stopping the alarm control module from locking the doors a few seconds after unlocking. My alarm system has a feature that locks the doors if after disarming, no door is opened... in case of accidental disarming... it's a cool feature, but i would've wanted the option to disable it. after all I just waned to use the keyless feature and not the alarm system.
since i couldn't defeat the consistent locking problem, i HAD to wire the module to the door open triggers... and since i'm doing that i might as well wire everything.

There's a feature which unlocks the doors automatically when you turn the ignition off... and locks the doors once you step on the brakes with the ignition on. Turn signal lights also flash when you open the door immediately after disarming... to alert traffic or something. pretty cool system for its price... (arnd 30USD).

would be even cooler if i didn't HAVE to wire everything though. hahaha

ah-kay · #10 01-04-2010, 09:16 PM

Quote:

Originally Posted by locry

update... tying the lines together didn't work for me. I'm not sure if the computerbox required a different polarity or the pulse was too quick...
anyhow, i just wired the trigger to a rear door trigger. I have yet to wire it to the front.

It is possible that the pulse it too quick or the electronic is different between brands. I used the parking light signal to tie to the door trigger and managed to defeat the 30sec auto lock feature. Well at least you tried as the concept is doable.