I have a 2005 g35 Automatic Sedan and the fuel gauge does not read gas correctly as it will say its full no matter how much is in the tank. Mechanic says I need to replace the instrument cluster but it cost $800+ from the dealer. I was thinking of buying it used but not sure if from other years will fit such as a 2006 or newer does anyone know if its the same and fit my 2005? Also would a G35x instrument cluster work on a G35?

 

Why are you assuming that you first need to replace the instrument cluster without inspecting, testing or replacing the fuel sending unit?

Have you or your so called "mechanic" consulted the FSM?

http://www.nicoclub.com/service-manu...5_G35_Sedan/fl

Read

" Check fuel level on fuel gauge. If fuel gauge indicates more than
the level as shown in the figure (full or almost full), drain fuel
from fuel tank until fuel gauge indicates level shown in the figure
or below.
NOTE:
Because fuel will be spilled when removing main and sub fuel
level sensor units for the top of the fuel is above the main and
sub fuel level sensor units installation surface.


As a guide, fuel level becomes the position as shown in the
figure or below when approximately 20 (5-1/4 US gal, 4-3/8
Imp gal) of fuel are drained from fuel tank. "

Telcoman