[Blas]

If you lift up the carpeting on the trunk floor (it's velcroed on) you will find a hatch cover that gives you access to the area where the fuel sending unit enters the top of the fuel tank. Remove the bolts holding the hatch cover on and there will sit the top of the fuel sending unit (most likely with one wire disconnected or shorted to the hatch cover) Look for a problem in this area
first...Email me directly if you have specific questions....(my email address is below)
If that does not appear to be the problem, we'll explore other options, but it's the most common reason for a dead fuel gauge....
FYI...The fuel system is a 10V loop not a 12V loop...And as always, be careful working around gasoline. Working outside the garage is always a good safety tip when working with open fuel tanks. But you should have no reason to open the tank top at this time.