If all the connections and wiring look good, it is probably the fuel gauge sending unit in the fuel tank.
Is the engine running ? no
Put a TV in it Also, if you have a built in gps in the car, that might take up the DVD slot so remove the navigation DVD
The sending unit in the gas tank is bad.
Speedometer, fuel gauge, and temperature gauge.
check battery cables at battery may be lose.
probably the fuel pump
Usually the gauge in on the dashboard with all the other gauges. That way you can read it while driving.
Yes 4 high ONLY .
Need to know year and engine size, That will help us answer your question. it's a 7.4 454 engine in a 1996 GMC suburban
A pretty reasonable assumption would be the thermostat is stuck open.
It depends on the setpoint of the thermostat.
Your fuel sensor inside the tank is shot. Change it.