Keyless entry -- W124 - PeachParts Mercedes-Benz Forum

mplafleur · #1 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.

Jeremy5848 · #2 05-11-2009, 12:03 PM

Quote:

Originally Posted by mplafleur

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.

I don't know if your S-class has the same locking system as my lowly pre-E-class . . . if it does, all you have to do is to access +12 volts and ground to power the keyless entry system and you need to break into one of the wires from a door lock. This can be either front door or the trunk/tailgate (as bobo said). The additional relays (easiest to buy the pre-wired accessory kit) allow the lock system to work normally with keys and knobs but also allow the keyless entry system to operate the locks.

You need to find out somehow whether the S-class lock system is the same as the lesser-classes. Maybe someone here will know.

Jeremy

bob_98sr5 · #3 05-31-2009, 11:53 PM

WARNING: One VERY wide picture!

Jeremy,

I was wondering if you could help me on my install. Its a different brand of keyless entry. I feel I'm close b/c the relays are clicking when I press the lock and unlock buttons on the remote, but the vac lock is not working.

I sent this to the alarm company yesterday, but if you can figure it out before them, I'd greatly appreciated. Their turnaround on an email is 2-3 days. Please see below:

Also, the manual calls for hooking up the starter wire to Relay 1 Pin 86 and Relay 2 Pin 85 to it. Is this the starter wire below? I could not find any other purple wires other than this one:

Thanks for any help!

scottmcphee · #4 06-03-2009, 03:10 PM

Don't make this hard.

Do it the easy way... Your trunk key will lock and unlock all the doors and trunk simultaneously, so dig out the harness going to the truck latch. I bought a $10 unit on ebay that came with 2 fobs (nice metal ones with lock and unlock symbols on two buttons). Mounted it on top of taillight inside the car with two-side sticky foam tape. The unit is about 2" x 3". Connected one output to one of these trunk latch wires, and the other output to another wire, even got constant +12 from that harness. Ground was easy to find in the area, and done. I did not bother re-connecting the harness to the trunk latch, because, I didn't believe this at first but it's true... once you have remote fob you'll never use a key in the trunk again, or in any door for that matter. Save your key for the ignition, that's the only place you'll need it. No wear and tear on the door locks which are famously difficult to change out...

The range I have is great, nearly 100' from the car. I like the nearly silent operation, with no flash or honk and any bull**** that advertises your car to a shopping mall crook who finds your set of keys left behind... and goes hunting.

ah-kay · #5 06-03-2009, 06:57 PM

Quote:

Originally Posted by scottmcphee

I bought a $10 unit on ebay that came with 2 fobs (nice metal ones with lock and unlock symbols on two buttons).

$10 is a good price? I need to do another project. Can you give us the link if it is still available?

bob_98sr5 · #6 06-04-2009, 01:40 PM

very intriguing scott re not plugging the rear trunk harness back in. i wish i knew this before! i'm tempted to look back there just to see and photo what you're talking about. im sure it'll help others avoid the pain of removing the seat and working with those short wires coming off the vac pump