99 SE Check engine and no volt reading on gauge

Hey guys, I have an issue on my 98 where the check engine light comes on and the voltage gauge drops to 9.

If I go under the hood and wiggle some connections the voltage meter runs back up to 14 and works for a while.

Now I am expecting a bad ground as the alt is only a few years old, as well as wiggling connections seems to fix the issue temporarily.

I hit a shovel someone kicked up on the highway that demolished the front passenger side corner grill, bezel turn signal and side marker light and this problem came soon after.

Can anyone thing of an issue arising from that that would cause this? Maybe a busted fixture or wire shorting out occasionally?

(my fat fingers caused me to mis-type the year!)

If you wiggle a connection and that causes the volts to go back to normal or improve or get worse.... That means there is something wrong about the CONNECTIONS you wiggled. Not saying you shouldn't check for bad grounds.. Just saying start with those wires you wiggled.