Hi!
I wrote that. Did you read the part how I determined where my fault was? Did you do a gauge sweep to see if your gauge or gauge brain is broken? Have you tried subbing a resistor or potentiometer to see if the gauge reads the values of the resistor / pot? Did you check the AC/DC inverter?
Lastly, I'd check all the connections, especially the external ones. If you have a damaged wire or connector, or a loose connector, its' not gonna work, and may not even trip an OBD code.
Good luck! (It's getting cold outside)
Shawn