Gas Gauge Reading Backwards

[g33kfu]

I just replaced the fuel pump assembly on an 05' grand prix non supercharged. The replacement pump was a used one pulled out of an 07' Impala. Everything works fine except the gauge is reading backwards (full when it's empty and empty when it's full). Is it possible to just switch a couple wires that are coming out of the assembly so the entire pump doesn't have to be replaced? If so does anyone know the wire colors?

Thanks

[olopezm]

Hello welcome to the forum!

As far as I know it sholud be enough to switch the wires on the level float inside the gas tank, I don't know the colors, but in my '97 grand prix these are black and it is very easy to distinguish them; as I mentioned before they are connected to the float assembly. Hope this info is usefull for you.

[richtazz]

The fuel pump is the same part AC-Delco part number (M10074 w/o level sensor) as long as the donor Impala wasn't flex fuel, but the fuel level sensors are different (SK1137 for your GP, SK1226 for the Impala). I'm not sure if reversing the wires would fix your issue, as they may be calibrated differently, or the float arms may be different lengths.

[g33kfu]

Thanks. Anyone have the wiring diagram so I can try out the wire switch? I hate to have to pull the pump again.