Good news is that in troubleshooting what I thought might be charging system problem I see 13+ v consistently. But I did make a weird discovery this evening.

The volt meter reads ZERO with the lheadlights on, I know it's inaccurate, but can it be that off?? Again, VM at battery shows 13.x steady.

bad ground somewhere and the gauge is drawing ground through the light filament.

Thanks. I assume that the center gauges share a ground as they connect through common harness. Where does that brown ground wire terminate at the vehicle body?

I don't know where the brown ground wire attaches to the chassis. Follow the brown wire from the center console to it's termination on the chassis.

You can always measure the voltage on both voltmeter wires by measuring the both wires to chassis. Connect one side of your multimeter to chassis and check the voltages on the back of the center console voltmeter. The brown wire should read 0V and the other wire somewhere around 12-14V.

Well, that turned out to be the easiest repair ever.

Pulled the gauge panel out and quickly saw that the ground wire to the voltmeter was not connected. That is the one the other center gauges piggyback off of so once hooked up I not only stabized the volt meter but I got my temp gauge working.

Feels like I am going through sea trials after the engine drop and other work completed. Yesterday I discovered a loose cone screw (thanks Chris from Tangerine for taking my call and diagnosing spot on).

A bit annoying given all that I paid the shop to go through everything after I put the engine and all back in. Heck, I noticed immediately the non functioning temp gauge and the weird VM readings.

Anyhow, thanks to everyone here, seems like the punch list is diminishing quickly and I will get to enjoy the rest of the summer driving.