My Honda would not start and when l popped the hood l saw that the positive terminal had all that acid gunk built up so l knocked it all off and l saw that the positive terminal was busted( the circle part) so l grabbed some pliers and clamped it together so my car would start. It started but as l drove home from work l realized my tachometer and speedometer were not registering anything higher than 0. What is causing that and can l just get the terminal connection and replace it myself? Will that fix the speedometer and tachometer reading as well?
Thank you! l replaced the connector and it started AND my tachometer and speedometer are in working order again as well!

It may fix it. Make sure there are no other wires that should be attached to the positive terminal. Then remove the negative terminal and clean that, too. Preferably with a wire brush, though, not by knocking it against the battery .

If that does not fix it, you may have a blown fuse or a bad ground wire to the instrument panel.