430 beeps after locking

Just some helpful info for anyone else running into this, I snagged a used siren from FerrParts for $80 on ebay; it's the newer style (green batteries) and they were both good @ >3v. I just swapped out my old siren and while it was also the newer style siren (so it was replaced at some point), it has the older yellow batteries, both of which had given up the ghost - 1 @ 1.4v and 1 @ .6v.

All better now and I've got a spare to solder in fresh batteries the next time this comes around.

 

The new one from eurospares cost me 100 bucks give or take

Also, remove the batteries from the one you are keeping as spare. When they start leaking, they do so like crazy (although they lithium, so chances are slim).
you will need some brute force or cutting, they are NOT soldered, they are spot welded in.