I had mine go bad about 3 years back and I ended up taking it to a band saw and cutting it open to see why it failed. It ended up being a NI-MH rechargeable battery that started to leak over the board causing it to short and make the alarm go off at random times while I was driving (that was fun). I removed the battery then soaked the board in a simple green/water solution in an ultrasonic tank for about a half hour. This removed all of the corrosion and cleaned the board up. After this, I soldered a new battery in and conformal coated the board to protect it if it ever happens again. It has been working perfectly ever since. If anyone is good with a soldering iron, you should be able to do this as well. The battery was only about about 10 bucks and I used JB weld Marine to seal it back up. Im testing my memory but I believe the battery was a Varta V150H like the one in the picture below. Just be sure if you do try to do this, you only cut through the outer layer of the plastic and not into the board. I just rotated the blade around the spot where it was plastic welded together little by little until it opened up. I like this method better because I could guarantee it has a new battery to survive the many years to come.