Car is overcharging. Please help!!

I would suggest you install a voltage guage and see what's really going on. To bypass the Amp guage correctly you need to use a crimp butt connector and solder. Then use shrink tubing to insulate the wires. All of your amps flow through that connection for the whole car. It also goes through the firewall connector which is another source of "Bad" connection. There are several articles about this by-pass which I would encourage you to at least read.

John B.