[olddog]

Just because you put new parts in, it does not mean all parts are working. You could have gotten a bad part. You could have installed something incorrectly. You could have shorted and damaged a part during the install. I'm not trying to be mister negative here. We all make mistakes, and when things do not look right, odds are something is wrong.

I recommend verifying your voltage with a good multi meter, if you have access to one. See what the battery voltage is with key off. Then see what it is with the engine running.

I'm thinking a battery should be a bit under 13 volts with the key off. With the engine running above idle, I would expect 13.5 volts give or take. I would check at the battery. If that is quite different than your gauge, then I would test again at the gauge to confirm if it is the gauge or the connections.