'85 300SD Alarm Problem

I hope someone can help with a factory alarm problem on my '85 300SD. It has started going off for no apparent reason and using the master key in the
trunk and the doors will not silence it. I assume some relay has failed.
I don't need to fix the alarm, I just want to disable it. I have pulled the electrical connection to the trunk vacuums diaphragm. I have taken the fuses out for both the horn and the locking system. Nothing stops the horn and lights from blaring whenever I open a door.
Can someone tell me where to look for the alarm itself and how to disable it?
Thanks,
Terray
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Open the front passenger door, take off the passenger floor mat, take off that lower mat. Now you should see black plastic panels both on the flat part of the footwell and the sloped part. The flat part plastic is held on with a screw. Take it out and take out the flat part plastic. Now push up on the sloped plastic to unhook it and pull it off. You will see to wiring harnesses on the backside of this sloped plastic, disconnect both. Richard

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