Voltage on 19V

Hi everyone

About a year ago my alternator failed and fried the battery and the voltage regulator in the PCM.

I installed an external voltage regulator. Since day one the voltage would rise to 19V when in reverse and every now and then rise while normal driving.

The alternator is good. The battery is good. I've cleaned up all battery cables and ground connections.

If the voltage gauge jumps to 19V and I measure the actual voltage on the battery it outputs 14.5V. This makes me believe that it could be the gauge itself.

Could it be that when the alternator failed that it fried the gauge too? Could it be something else?

It's a 98 4.0 model.

Any input would be appreciated

If I recall correctly, the gauge could be using the 19v position to indicate a failure of some kind, or be faulty.
Mine was just pushing too much voltage due to a broken regulator, but it didn't go all the way to 19v and the reading at the battery was consistent with the gauge.