On my '86 300E, the alarm modue was under the passenger floor mat. I needed to remove both the flat part and the part which slopes upward. The module can be disconnected by unplugging the connector on its side. I disconnected mine because humidity caused false triggers.

Hope you can get the car out in time. Don't put yourself at risk, you can always get a new car. That is one scary storm.

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1986 300E
1993 Volvo 940 Wagon
1984 Volvo 240 (daughter's)
1976 Dodge 1/2T pickup, gas hog