18 volts at the battery- Help...

[kxnomore]

I just hooked up a new front wiring harness from Classic Parts and now I've got 18 volts to the battery. Does anyone know what may have gone wrong?

The truck has an alternator, and I hooked up the blue/ white double connector to the back of it. Then the red wire, of course. And there was a black wire that was disconnected before and hanging loose, so I duplicated the same thing this time, too. So the black wire that is taped to the other previously mentioned wires is not hooked up. Could that be it?

The voltage regulator was hooked up before and is hooked up now too.

Plus the truck just started running really rough. I mean shaking like an earthquake rough.

Thanks in advance.