1998 Buick Skylark instrument gauges

Ok, a little history: the car was in a wreck and the front end had some exterior damage, it has been sitting for approx a year or so.I replaced battery fender and radiator. Got the car running ok, but the alternator is putting out 15 (?) And when the car starts, the temp gauge works and starts climbing, but when it reaches like a quarter of the way up, it stops working, and all the dash lights stay on. Oh yea, the key that I have is a remade key, not the original one, and I had to shave down part of the sides, not the part that goes in, just like the ears so to speak to get it to even go in. What kind of anti theft does this car have? I just replaced the alternator with one from pick a part and it is doing the same thing