One way to check for faulty voltage regulator [over voltage condition] is to test battery voltage with a multimeter while hte engine is running ...

You should get max 14.5v with engine running at 2000rpm... more than that probablly means your voltage regulator is bad and overcharging the battery >> at leats that's the procedure I use to test my 911 alternator..

electrical grounds [or lack thereof] are also noted for making things weird in cars... check all your grounds..