MAJOR problem! Please help!
 

Ok, so I needed to change alternators on my 2.3l because mine was really getting loud. So I get a used one and installed it. I accidently left the battery connected when installing and when I started it, the battery gauge went through the roof and the batt. light was on. I talked to the person I bought it from and said to drive it 30 miles or so to see if the battery was low and was in need of charging. So I did and that didnt do anything. So I disconnect the battery and reconnected it later and started it up. The gauge went down a bit and seemed to drive fine. So the next morning I go to start it and its dead as a door nail. So I hook it up to the charger and around 5 in the afternoon start it and it went back the having the gauge go way up. But when I turned on my head lights, freaky things happen. The battery gauge goes down to the bottom, the temp gauge goes way up kicking on the fan, the tach goes to way below zero while running and the brights are stuck on along with the blinkers. I have a new battery and the had the alternator double checked and it is fine. Is this an electrical short or something else? Its a 90 and I'm trying to sell it and this is really looking bad. Any info is greatly appriciated.

Well, a similar thing happened to me awhile ago with my 140amp alt. The alternators are internally regulated in all Fords. It is very possible that the regulator is bad in it. This will cause the weird electrical stuff that's going on. I would just go to Autozone and buy a new one for $80. That's what I did to my bros Mustang and hasn't have a problem yet. You can rebuild it but if you aren't mechanically inclined then I would not suggest it. Hope this helps ya out.....

I would get a new one. Old alt that have been sitting for a while, tend to act up. I bet money, if u get a new one. things will work out great.

This is true. This is why they don't like to sit around.

Thanks for the advice. I could either return this alternator and go with a new one online from AutoZone for 120 plus a core value of 40, but there isnt an Autozone close to me but I can order online. Or I could take it apart and put a new regulator from Autozone for 15 dollars. Which do you think would be my best bet for the money?