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2016 E350 wagon; 1994 E320 wagon
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8,005 Posts
Discussion Starter · #1 ·
so, on 94/95 cars with the alarm, like my 1994 E320 wagon, there is not only the alarm module under the passenger floor panel but also an immobilizer relay that disables the starter motor, this is located on the firewall behind the instrument panel and is a SOB to get at (#@[email protected] mechanical speedo cable being the biggest pain to get around).

I really didn't want to get in there to bypass that relay, so I studyied the schematics (which ARE on the W124 CDs, they just aren't indexed, its w124CD1/Program/ETM/2482400.pdf if you have a set), and I realized that on ATA connector 1, if I jumpered pins 1 (the immobilizer relay coil) to ground (pin 2, right next to it), the relay would stay on, and all would be happy. further, the other side of the relay coil is on ignition circuit 15, so its not even draining power when the car is off, bonus!

one quick jumper wire and poof, we got NO MORE ANNOYING ALARM, that always goes off at the most EMBARRASSING possible moments, requiring the driver to jump out of the car, and work the driver door lock from the outside.
 

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12 odyssey (90k) 1995 E320 wagon (307k) 1983 500se (172k) 1995 Cabrio (123k)
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3,392 Posts
Sweet!
Great sleuthing. The forum gods are smiling on you.
 

Premium Member
2014 G550, 2000 SL500, 1995 E320 Cabriolet, 1980 TR8
Joined
1,747 Posts
Yes, indeed, that is the best way to disable the starter-inhibit function: http://www.benzworld.org/forums/w12...-can-i-disconnect-my-alarm-2.html#post7491145. I'm glad you figured things out from the schematic. I've been more or less off-line after I broke a rib and blew out an elbow while skiing so I just saw your original thread and with regard to that, I would like to add that the biggest issue with alarm un-reliability is probably the ATA module itself. Like all modules on these cars, they are getting old enough that solder joints start to fail from heat cycling and vibration over the years. The other place to look for "falsing" is the pin switches under the hood, seat, etc. along with the door and trunk switches.

- FD
 

Premium Member
2016 E350 wagon; 1994 E320 wagon
Joined
8,005 Posts
Discussion Starter · #4 · (Edited)
what was annoying is that it typically didn't go off when I opened a door, instead it went off when I tried to start the car.

if I unlocked with the TRUNK lock, then the drivers door would probably set it off. but if I unlocked it from the drivers door, get in, sit down, seat belt on, key in ignition, start <HONK HONK HONK HONK> oh crap, jump out, and put key in door again.

p.s. I just fixed the index for the 1993-1995 ETM on the MB W124 CD set and submitted it to the W124 CD index .... hopefully there will be a new release soon.
 

Premium Member
2016 E350 wagon; 1994 E320 wagon
Joined
8,005 Posts
Discussion Starter · #5 ·
p.s. I just fixed the index for the 1993-1995 ETM on the MB W124 CD set and submitted it to the W124 CD index .... hopefully there will be a new release soon.
and, done, a new version of the W124 CD Index has been released which fully indexes the 1994/1995 ETM.
 
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