First time posting for me hopefully it will be successful. Over the past 2 weeks my 1988 XJ in dash gauge has been jumping between 9 & 14 volts. At first it seemed like it dropped when I was in gear and the ended up doing it in neutral and idling. Very recently I tested the charge and decided that the alternator was done for. I swapped alternators and I still have the same problems. The next thing that came to mind was maybe it’s the regulator; however they are built within the alternator. I can’t imagine the regulator being shot on a brand new alternator so I simply ruled that out. Basically now I’m sitting scratching my head wandering what it can possibly be. Basically no charge going to the battery. Advise please…. Thanks, DK