flasher, AC light -> bcm problem?

My flasher works properly except that it sometimes clicks even without turn signals energized or hazard switch on. I've replace the flasher but it didn't fix the problem. Also, the AC indicator light intermittently goes off for a few seconds and then comes back on, and the AC compressor turns off at the same time. A few months ago, I noticed wet carpet on the passenger side so there may have been a water leak through the firewall somewhere. Since the BCM is common to both the AC and flasher, I suspect that maybe it is water damaged and corroded. Anybody have any other suggestions about the problem? Are there BCM codes that can be read out (I've scanned out all the codes through the regular PCM connector under the dash but it didn't pick up any BCM problems).

By the way, it's a 1999 Malibu.