After changing 06 prius 12 volt battery, gas gauge has one blinking bar

If you bought an Optima battery, that's likely the problem... Return it! They're junk batteries... But if your new 12v is fine and there's nothing wrong with the wiring/connections, the always problematic gas gauge calibration will likely resolve itself after a cycle or two of filling up.

 

welcome!

not sure if this is it, but try searching 'gas gauge reset' for directions.

but maybe it's just the leftover unconnected wires?

 

Relax, anytime the 12v power is interrupted, the gas gauge defaults to one blinking dot. My 2007 typically starts indicating correctly within 10 minutes. The 2005 I recently bought took a day.

You also lost your radio settings and the auto up/down feature of your power windows. Reset the windows by holding the switch in up position until the window is fully raised + about 10 seconds.

Not sure what you're describing being next to the battery, but the only item next to the battery that I remember is the capacitor bank (black box) used as emergency power for the brakes. It only has one connector and I think it has like 9 or 10 wires. The only one wire connector in that area that I remember is the one that plugs into the (+) battery terminal block assembly. I think that's the voltage sensing wire used by the inverter. (may be wrong on that)