1985 300D with the factory alarm. A couple times lately I have opened the drivers door with the key and the alarm will go off. I have to shut the door and relock it with the key a couple times to get it to shut off. It has also gone off shortly after starting car. This only happens during the day when it is really really hot outside (phx 110+) don't know if that has anything to do with it though. This has only happened a few times but it has me concerned.

How can I disconnect the alarm all together?

Thanks
Kevinlee

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Mercedes 1985 300D 240k
Volvo 1985 240GL 260k

As per the w126 the alarm is a black box under the front passanger floor carpeting. Just disconnect the plugs from the box. I'm guessing the w123 layout is similar.

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Dmitry

Where on the floor is this located? There is a little trap door on the passenger side under the dash in front of the door bascily with a black box in it. Could that be it?

Kevinlee

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Mercedes 1985 300D 240k
Volvo 1985 240GL 260k

I pulled up the carpet and it's not under there. The little trap door on the side under the glove box has a little round thing that says egr and some numbers. It looks like a flasher for turn signals on some cars. Theres also a black box in there but I can't see any markings or wireing on it.

Is there another way to disconnect alarm?

Kevin

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Mercedes 1985 300D 240k
Volvo 1985 240GL 260k

I had the same problem with my 300D. I had my mechanic disconnect it. It is not the floor. He had to remove the panel above your left knee. That is where it is, but you must know what to disconnect, You could do it by trial and error... if nec....

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'87 924S
'81 280SEL

Sold ->

81 300SD -
93 300E w/ 3.2
85 300D-
79 300SD
82 300CD
83 300CD - CA
87 190E 5 spd
87 Porsche 924S

"..I'll take a simple "C" to "G" and feel brand new about it..."

Unhook the horn from the end of the system?
Will your car run with the alarm sounding?

Yes it runs with the alarm going. I'm not sure where that alarm horn is. I thought about diconnecting it there but when I stuck my head under the hood with the alarm going off it more than I could deal with at the time. It's loud...

Kevinlee

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Mercedes 1985 300D 240k
Volvo 1985 240GL 260k

If it makes an "arm/disarm" noise when you are arming it, etc...then you can have someone do that while you seek out the horn.
Little short blasts are a lot more withstandable than the ungodly loud horn...