The security system has been acting up for years. It drained the battery

But now with a new battery I have the same problems. A couple of years ago the security system of my car started acting up. It would chirp randomly and occasionally. A typical example would be that it would start to chirp every few seconds to every minute or so, sometimes more frequently, sometimes less, until I unlocked and locked the car a number of times with the keyless entry system. When the car was chirping like this it would not start. The lights were on and the battery was fine, but the engine would not do anything because it was locked by the security system.

Recently this problem was getting worse. Also, on two occasions the horn started "screaming", and I had to push it in various ways to get it to stop. My battery got drained a couple of times because I could no longer get the chirping to stop.

I brought it to a mechanic specializing in electrical problems, but they could not find what was wrong. They said that the battery was weak and replaced it. When I picked up the car it was not chirping anymore, and the keyless entry system seemed to be working as well. I brought it home though, and now, a couple of days later, the battery is dead again even though it has been quiet.

The other thing that may be related is that my car has has problems with water leakage for quite some time. I've brought it in to be fixed but nobody has been able to solve the problem. I'm concerned that this may have damaged wires, though the I'm living in a relatively drier place now that I have before, which should have helped this problem, not made it worse.