1997 blazer gas gauge malfunction

We recently replaced the fuel pump sending unit and connectors on my blazer the gas gauge was working properly before we replaced it and now all of a sudden it is not working at all it reads a full tank! What could be the problem and how can I fix it?

We recently replaced the fuel pump sending unit and connectors on my blazer the gas gauge was working properly before we replaced it and now all of a sudden it is not working at all it reads a full tank! What could be the problem and how can I fix it?
That is a long tall question.:sarcasmsign:
But it.
Sounds like lack of proper installation and or testing and understanding of how the fuel gauge works.

The fuel tank sending unit grounds the dash gauge out put voltage threw a varable resistor to make the dash gauge work.

First thing to check for is proper ground and wiring to fuel tank pump and sending unit.
Then check for voltage from dash gauge.
If votage there then ground the wire fr only a few seconds and see if fdash gauge swings from full to empty or empty to full.
If so then dash gauge is working.

Then check the ohms restiance on wire to fuel tank sending unit.
If it has ohm's restance it should be working dask gauge.
If not confirm good tank ground and wiring wired right to tank unit.
When rewiring the tank plug confirm which wire goes where and pitch the butt connectors.
Solder the wires and heat shrink and use sealer to.