New to forums, but would appreciate electrical help
 

Hello, I am new to joining any forum, but I could use some help with my '97 vanden plas. have taken the alternator off, taken it to get it check at a auto parts store, they say it is ok, but as it is running, the gauge reads 9, or even in the red. it will stall at stops frequently. the battery while off reads 12.01 volts. kinda wierd how it will still run at below 10 volts with A/C on. Any help is greatly appreciated.