electrical problem, maybe alternator?

[03blackZ]

Hey guys I'm new to the forum and I'm hoping someone might be able to steer me in the right direction with a recent problem I have with my tahoe. I just had a check engine light come on and the tahoe went to reduced engine power mode. I restarted it several times and the engine light and reduced power mode never went away. I then noticed the volt guage was pegged at 19. A couple of days later the light and power mode are gone but my oil and gas guages are all out of wack. I noticed the battery has a slight mark as if water may have boiled out. I had the alternator tested and its reading 15-15.5 with load. Anyone have any idea what could have caused this? I know the tahoe's have a problem with the instrument clusters but I don't think that would have caused the reduced engine power mode to come on. Could a overcharging alternator caused all of this?

 

[DefEddie]

If you have dropped a cell in the battery then it will cause all sorts of wackiness like this usually,so get it checked first.

Take it to a shop otherwise,if you have no electrical experience it could be too much.
Your regulator could be allowing your alternator to overcharge,but the regulator is controlled by the PCM.
So the regulator could be not listening,the PCM not talking correctly or an issue with the circuit in between.

Have the battery checked first though!