Keyless entry -- W124 - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 05-09-2009, 11:34 PM

I finally got around to installing the keyless entry system (bought in January, good grief) in my 124. The system is an Omega REC-11 (about $24 on eBay). This system has been discussed in this forum and some good advice posted.

I did a very simple install of the system, just laid the parts on the floor of the car under the rear seat and wired into the pump. The receiver and relays aren't even attached to anything, they just sit on the insulation. I didn't buy the extra-cost relay pack as I had lots of automotive relays.

I didn't use any of the optional extras that the Omega REC-11 supports, like the light flasher or the self-destruct circuits ["Warning: you have broken into a car equipped with the new Omega self-destruct mechanism. Self-destruct will occur in 10 seconds . . .9 . . . 8 . . ."]

As other threads have covered installation thoroughly, I'm not going to repeat. I'll mention only a few notes:

(a) I removed some unused wires from the main connector, including a connection to the "hot in run or start" lead. Without it, you can't program the system, but I found I didn't need it. I didn't use either the LED or the "valet switch."

(b) In my W124, the stock 0.8 second delay time is sufficient for locking and unlocking. Omega gives you an option to change this to 2 seconds (recommended for Mercedes) but so far I've been OK without it.

(c) Owners of "later model" Mercedes with an electric pump for door locks know that you can't lock the doors from the outside with the key in the ignition switch (engine running or not). There's a circuit that is part of the "key-in buzzer" to prevent you from doing this. I think you can go around to each door and lock it with a spare key but that's a hassle.

Well, the keyless remote allows you to lock the car from the outside with the engine running. This allows you to warm up the car in the morning (if you do such things) without getting the car stolen. It allows you to let the car idle (staying warm or cool) while you run into the post office to pick up your mail, again without leaving the car at risk, unlocked.

With my W123, I could do that simply by carrying a spare key. Now I can do it with the W124 also.

Jeremy

compress ignite · #2 05-10-2009, 01:36 AM

The "Clownistas" who did mine for the PO used the AutoMate (which works fine)
BUT the Brain is in Under Portion the Driver's side Footwell.
[Too much chance,for Moisture Mischief,So it's gonna move]
(I'll bet they've got it tied into the Driver's Door Electric Key Switch...Hmmmm
if that's so, would activating the UnLock function on the Remote for 10 seconds
trip the "Convenience" function and roll up the Windows and close the S'Roof?
AND Vice Versa ... I could really get into being to open Windows and S'Roof
Remotely, to cool off the Passenger Cabin!)

[Sorry to semi-hijack your post]

bob_98sr5 · #3 05-10-2009, 02:03 AM

jeremy,

as always, i am always 1 step behind you. thanks for posting w/ pics. i actually had this on my "to do" after I finished w/ my biodiesel processor which is still weeks away from completion.

aside from lifting up the backseat to get to the rear vac pump, did you need to undo anything else? door panels? I do plan to install a complete matching set of door locks and ignition. do you think I should do that first? I can always put that off without any repercussions.

compu_85 · #4 05-10-2009, 02:16 AM

Quote:

(c) Owners of "later model" Mercedes with an electric pump for door locks know that you can't lock the doors from the outside with the key in the ignition switch (engine running or not). There's a circuit that is part of the "key-in buzzer" to prevent you from doing this. I think you can go around to each door and lock it with a spare key but that's a hassle.

Does it know this because of the alarm switch in the driver's door lock? I don't think my W126 is like this.

-J

Jeremy5848 · #5 05-10-2009, 11:27 AM

Quote:

Originally Posted by bob_98sr5

. . . aside from lifting up the backseat to get to the rear vac pump, did you need to undo anything else? door panels? I do plan to install a complete matching set of door locks and ignition. do you think I should do that first? I can always put that off without any repercussions.

One of the beauties of the Mercedes door lock system is that you don't have to pull the door panels, kick panels, or under-dash panels. Everything is done under the rear seat. Caveat: W123 and older cars need to have an electric actuator installed inside the driver's door and wires fished through to under-the-dash. That one was more work.

You can install the matching set of lock cylinders before or after, it really doesn't matter. You may find the keyless entry so convenient that you stop worrying about the mis-matched keys. If your vacuum/pressure pump and actuators are working correctly, the remote will lock and unlock everything.

Jeremy

Jeremy5848 · #6 05-10-2009, 11:31 AM

Quote:

Originally Posted by compress ignite

. . . (I'll bet they've got it tied into the Driver's Door Electric Key Switch...Hmmmm
if that's so, would activating the UnLock function on the Remote for 10 seconds
trip the "Convenience" function and roll up the Windows and close the S'Roof?
AND Vice Versa ... I could really get into being to open Windows and S'Roof
Remotely, to cool off the Passenger Cabin!)

[Sorry to semi-hijack your post]

I've wondered about that. The early W124 doesn't have the second convenience module so I've never figured out how to do the window/sunroof trick. Sixto and I did figure out how to get the power windows to work with the door open/key off, just like the power seats do now. But that's not what you want. It could be done--no question it is possible, especially with all of the extra functions that modern keyless entry systems have.

Jeremy

Jeremy5848 · #7 05-10-2009, 11:41 AM

Quote:

Originally Posted by compu_85

Does it know this because of the alarm switch in the driver's door lock? I don't think my W126 is like this.

-J

It is because of the switch in the ignition lock cylinder. In the W124, and should also be in your W126 and the older W123, putting the key into the lock (without even turning it) trips a microswitch. What that switch does depends on which year and model you have, there are probably many variations.

In the early W124 (my '87 300D), the switch interrupts the ground in the vacuum/pressure pump circuit for the passenger door and trunk/tailgate. You can lock those doors with the key but the pump circuit won't work to lock the other doors. Locking the driver's door from the outside won't lock the other doors either but I haven't figured out why. Perhaps the PO left me with (another) "new feature."

I understand that in the W126, the pump is in the trunk. It should otherwise work the same.

Jeremy

Jeremy5848 · #8 05-10-2009, 12:29 PM

I was wrong! (first time ever!

)

You CAN lock the W124 (all doors), outside with the key in the ignition, even with the engine running, using a spare key. The reason I couldn't when I first had the car was probably due to the boogered wiring inherited from the PO. The idea got stuck in my mind and I never checked, until just now. One of the repairs I've made over the past couple of years fixed more than I realized. Wow, I'm good! Fixed more than I thought I did.

The keyless entry is still nice. I'm keeping it.

Jeremy

::matthew · #9 05-10-2009, 12:51 PM

has anybody added a electric pump in the w123 to mimic the 124 setup?

I guess the vacuum actuators are different in the doors (especially the driver's)

I have a pump and have considered it.

compress ignite · #10 05-10-2009, 02:47 PM

You'd have to find the Vacuum feed line for the locks and splice the Electric Vacuum Pump's line into it(and close off the Vacuum Line that lead back to the original Mechanical Vacuum System)...AND then wire the Keyless remote to the Electric Vacuum Pump.

Wait a minute...It Might be a little more complex than I've portrayed it!
You're correct Matthew,the challenge would be adapting the Driver's door
mechanism.

from the 123.132 Chassis:
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=123132&M=617.912&GA=722.118405&GM=716.005++++++++++++++717.400&CT=F&cat=222&SID=80&SGR=045&SGN=02

bob_98sr5 · #11 05-10-2009, 02:50 PM

Jeremy,

Thanks for the info. Yeah, i am not looking forward to changing out all the locks, but having 1 key vs 2 is definitely something I'm looking forward to.

Bob

Jeremy5848 · #12 05-10-2009, 05:11 PM

Quote:

Originally Posted by compress ignite

You'd have to find the Vacuum feed line for the locks and splice the Electric Vacuum Pump's line into it(and close off the Vacuum Line that lead back to the original Mechanical Vacuum System)...AND then wire the Keyless remote to the Electric Vacuum Pump.

Wait a minute...It Might be a little more complex than I've portrayed it!
You're correct Matthew,the challenge would be adapting the Driver's door
mechanism.

from the 123.132 Chassis:
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=123132&M=617.912&GA=722.118405&GM=716.005++++++++++++++717.400&CT=F&cat=222&SID=80&SGR=045&SGN=02

Agreed. In the W124 and similar cars, the lock system is far more complex. Each door (both fronts and the trunk/tailgate have an electric switch as well as a mechanical link to the vacuum actuator. To use a W124/126 electric vacuum pump, you'd have to swap in the entire system. Certainly possible to someone with access to tools, knowledge, experience, and maybe a machine shop.

Hmmmm, actually it's worse than that. The 123 cars use vacuum to lock and unlock; the 124 (and maybe 126/201?) use vacuum and pressure. The pump runs one way to create vacuum and lock the doors; it runs in the opposite direction to create pressure and unlock the doors--or maybe the other way 'round, but you get the idea.

Jeremy

Jeremy5848 · #13 05-10-2009, 05:12 PM

Quote:

Originally Posted by bob_98sr5

Jeremy,

Thanks for the info. Yeah, i am not looking forward to changing out all the locks, but having 1 key vs 2 is definitely something I'm looking forward to.

Bob

I had to replace the tumbler in my 87's ignition switch for exactly the same reason. Much nicer to have just 1 key and the tumbler swap was easier than I thought. Still $100 though.

bobodaclown · #14 05-11-2009, 10:42 AM

Did it on my W124. Only need to cut into the trunk trigger line (electric). Works great.

mplafleur · #15 05-11-2009, 11:52 AM

Quote:

Originally Posted by Jeremy5848

I finally got around to installing the keyless entry system (bought in January, good grief) in my 124. The system is an Omega REC-11 (about $24 on eBay). This system has been discussed in this forum and some good advice posted.

I did a very simple install of the system, just laid the parts on the floor of the car under the rear seat and wired into the pump. The receiver and relays aren't even attached to anything, they just sit on the insulation. I didn't buy the extra-cost relay pack as I had lots of automotive relays.

I didn't use any of the optional extras that the Omega REC-11 supports, like the light flasher or the self-destruct circuits ["Warning: you have broken into a car equipped with the new Omega self-destruct mechanism. Self-destruct will occur in 10 seconds . . .9 . . . 8 . . ."]

As other threads have covered installation thoroughly, I'm not going to repeat. I'll mention only a few notes:

(a) I removed some unused wires from the main connector, including a connection to the "hot in run or start" lead. Without it, you can't program the system, but I found I didn't need it. I didn't use either the LED or the "valet switch."

(b) In my W124, the stock 0.8 second delay time is sufficient for locking and unlocking. Omega gives you an option to change this to 2 seconds (recommended for Mercedes) but so far I've been OK without it.

(c) Owners of "later model" Mercedes with an electric pump for door locks know that you can't lock the doors from the outside with the key in the ignition switch (engine running or not). There's a circuit that is part of the "key-in buzzer" to prevent you from doing this. I think you can go around to each door and lock it with a spare key but that's a hassle.

Well, the keyless remote allows you to lock the car from the outside with the engine running. This allows you to warm up the car in the morning (if you do such things) without getting the car stolen. It allows you to let the car idle (staying warm or cool) while you run into the post office to pick up your mail, again without leaving the car at risk, unlocked.

With my W123, I could do that simply by carrying a spare key. Now I can do it with the W124 also.

Jeremy

Can you be more specific on how you wired this into your pump? I have an '86 SDL and I hope I can assume your locking system is the same as mine.

I was under the impression that I would have to wire a solenoid into the driver door and there was nothing at the pump I could do.