Yesterday, 1/20/17, I removed my old siren and install new one. Cleaned out the drain holes in the cowl, applied a cream to the cowl cover, getting sun burned. I found out for some reason, my new siren, which I bought from Mercedes part dealer, was suppose to chirp. mine doesn't. Either it is a non - chirper, or some how I missed something. I took the ordering number from 180's posting, it is a plug and play attachment. It will not go in backwards. It fixed my problem of the alarm system going off after setting it. So over happy, I can again lock my car up, Next project, new thermostat and replace antifreeze solution.
I forgot to include that I also put new Isolators on the windshield wipers. And thanks to Onehundred 80s' post, on how to do drivers side, one top from a gallon container of ice tea work perfectly.