Yesterday my AIR BAG lamp turned on, I went to dealer and code was "high voltage". Checked voltage - it was 16V.

So I went to alternator shop. They changed voltage regulator. I put new battery in, cause old one had black water inside from overcharging. Started the car and same problem - 16V.

They said they checked it after they installed alt on their battery it was ok. But now it's again 16V.
Also when I turn key to ON with engine shut down - battery lamp on the clauster blink randomly. WTF?

Any guesses? Help.