1993 mercedes 300ce door lock issue

Have an issue here and was wondering if anyone on here ran into the same issue or knows Mercedes better than I do. Any help would be greatly appreciated. So about two weeks ago I installed a standard alarm (avital 3100l) into the 93' 300CE. I got nearly all my connections from the OEM alarm located at the front passenger foot-well behind a big flat metal bracket. I got the door lock wire (blue or green)at the vacuum supply pump located under the rear passenger seat. I also disconnected the OEM alarm after I made all my connections ( 2 door triggers, trunk trigger, ignition, power/ground, and parking lights)to avoid triggering factory alarm with the key. After install everything worked great but now a week later the door lock/unlock funtion doesn't work with the new alarm remote. I here the relays click but nothing. So I try to unlock the driver door with the key and it unlocks the driver door but not the passenger door or the trunk like it use to. I go to the passenger door and with the key all both doors and trunk lock and unlock. So to me that ruled out 1)faulty supply pump 2)faulty door/trunk actuators I go to the vacuum pump were I made my connection (BTW, there are two plugs. one with two green and two blue wires. the other with one green, one blue, and one yellow) I use the top plug with two blue and green wires since they all tested the same with a DMM. Then I switch the wire from the blue to the green. Now both doors do nothing with the key????? It must be some kind of signal problem coming from door or some control unit but I'm stumped at this point.

i did one of these just like this a long time ago and just like you it came back a few months later because the locks stopped working but the problem turned out to be a bad pump. how did you wire the locks? there was a special way they needed to be wired and the lock pulses had to be 3 seconds or longer. and there was also the other wire that needed to be cut with a relay at the same time. this was all a very long time ago so my memory is sketchy. it sounds like to me that the wire you used to activate the pump was the wire that gets its signal from the drivers door switch and now that wire is dead, either inside the door or inside the control board for the pump. tell us how you had everything wired and we can go from there.

Green and blue are the front door triggers, yellow the trunk. 3 second delay shouldn't be needed on a 93. I concur with soundnsecurity, driver's door switch has failed. BTW I never bothered to go that far back for the lock trigger pick up in the rear, go to passenger door and pick up the blue or green in the floor loom, in a separate "tube" with a RED / white (12v+) and a BROWN / black. Incidentally if you want to waste that much time you should have gone to the plug with the blue, green and yellow wires. The second method is to open up the lock pump, underneath the pump motor wires, red and black, 5 wire them. Very complex and NOT recommended to any one not used to stripping them.

Update:- Blue, driver side green passenger side. "Tube" mentioned above, brown, not brown black. There's also a total (comfort)close wire adjacent I believe yellow blue on the passenger side, also floor loom, ground after lock for about 15 seconds or add a 528t if the 3100 doesn't support a timed aux, active on locking.

thanks for the quick feedback to both above, So I wired two relays together to control the vacuum door lock system and I wired them exactly as instructed on my Directechs door locking guide for type E door locks. The exact same diagram is offered here also in the relay section of this site. At first I tried using a 3.5 second pulse but that made the windows behave badly, so I programmed the avital 3100 back to default 0.8 secs and that worked fine. The wire I cut in half was located at the vacuum supply pump harness under passenger seat. Like I said there are two plugs. One plug has just one blue/GREEN/ YELLOW wire. I left that one alone. I used the other plug which has two green and two blue and I believe two yellow wires. The blue wire did test right with my meter. Howie II, I could find the green wire at the passenger kick and I searched in every loom. Which is why I went directly to the pump. Tell me more on how to 5 wire the door motors because if I have to do that I will. Esp, if something went wrong for the control unit or switch. I was even considering adding my own door actuator's I have in my tool box DEI 524N. Whatever I have to do to avoid a trip to the dealer.

a few questions, have you checked your fuses for the alarm and the car and any other fuses you might have added? have you tested the relays with a meter to make sure they are working and not stuck or possibly fried? its rare but it does happen... also i dont think you can just add electronic actuators to that car without basically replacing the whole lock system because the lock rods are nothing but tubes.

well I have checked the fuses under the hood Fuse C and A look OK but I haven't checked them with a meter. And as far as the relays I just listened to them click so I guess I should check them with a meter too. I just had the idea of using electronic actuators but I haven't removed a panel and looked too see if I could rig something. That would be my last resort. I put everything back to stock and spoke French to the control unit hoping it would just spring back to life but no luck. Now Howie II mentioned 5 wiring the motors which seems like a great idea. I now the colors for the motors are RED / white and brown (BROWN / black pass. front) and triggered by the blue and green wires. But does the vacuum/vapor supply pump NEED to play a role in it all? You say there are no rods just tubes?

I can see we are going to have conceptual problems here. The colours you last described are the SWITCHING wires. They don't actually move the pumps. The pump motor under the back seat moves the pumps. BROWN / black and RED / white are the POS (+) and NEG (-) supplies to the green, blue and yellow. Yes they are hard to find. It's called perseverance. Actuators, forget it no room in the doors, been there and tried that. The ACTUAL motor is in the pump under the rear seat NOT in the doors. You lift it up from its position and gently prise off the bottom plastic plate you will see RED and BLACK motor wires going to the pump. The problem being that if you couldn't find those wires in the floor looms, how are you going to take apart that pump? It's a bit akin to brain surgery. Look here for a description of 5 wire control in the relay section.

i would at least troubleshoot and eliminate any other possible problems first before hardwiring the pump because if it is something else causing your problem then hardwiring the pump wont do you anything and you risk destroying the pump if you botch the wiring. im pretty sure that pump aint cheap.

Howie II,

Thanks for clearing that up, actually the pump under the passenger seat is really easy to get to. The passenger kick was like a German maze, so I left that alone.

So basically there is this power connector with three wires on it RED / yellow (12+ @ pin 3), BLACK / YELLOW (IGN @ pin 2), and and two brown ground wires together at (pin 1). The two other connecters with blue / YELLOW /GREEN wires are like you say signal wires coming from and going to doors and OEM alarm some way or another. All the b/y/g wires tested the same 12+ while 2 front doors/trunk unlocked and GROUND while locked. So those were all fine. the wires at the power supply connector tested fine as well. The BLACK / YELLOW igntion wire actually terminated at the plug, so it never connects to the pump at least not on this model M. Benz.

So, I unplug this power harness, but this time a speak Spanish to the pump. Plug the harness back in and the darn then springs back to life!!!

Good Lord!

If it goes wrong again now I'm certain it's a faulty pump.