I made an appointment with my mechanic to have new windshield washer nozzles and a new hood strut installed and the siren module removed. It's still working, but I assume that any day now the 20-year-old module battery will dump all over the circuit board and become the apparently ubiquitous parasitic draw that will kill the car's battery.
I can no longer bend far enough to reach into the engine bay, and the shop I go to has done all the work on our Crossfire so I trust them.