I'm having similar issues. I've replaced alternator within past three years, battled some tensioner issues. Then corrosion claimed most of my battery and attatched wires. Will be adding 4ga ground wires ontop of stock locations after some cleaning of mounting locations. However I'm hesitant to believe this will solve my problem, as the car started fine when I left car unlocked in garage for three days, but when I locked it after driving around next day it was dead within 12hours. It's like everything using a 12v source decided to evil dead on me.
Would there be any code logged for the alarm failure/fubar, or will I literally have to test the reset on module? I was tempted to add a battery kill switch to save me unhooking it every night, but I'd much rather actually solve my problem rather then bypass it. I'm sure corrosion of wire ends was a factor in this, the terminal wires had 6-9 inches of white/green flakey insides rotted, couldn't tell from outside the wires until I cut into it.
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