The radio is indeed wired to the factory alarm. The box mentioned above monitors the doors, hood, trunk, and the radio. I once had a loose radio in a 190E that would set off the alarm while driving down the road. That was quite a sight!

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
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