I Have 2 problems.1. The fuel gauge stays on full. 2.The seat belts won't function.

Replacing a fuel pump has nothing to do with instrument cluster lights or the clock staying on. Unless you shorted wires , did you disconnect the negative battery cable before hand ?
The body control module (BCM) performs the following functions:
• A/C compressor request
• A/C cooling fan
• Exterior and interior lighting control
- Daytime running lights (DRL)
- Automatic lighting control
- Fog lamps
- Interior lighting
• Battery rundown
• Chime
• Gauge control
• Instrument cluster indicator control
• Fuel gauge control
• Temperature gauge control
• Theft deterrent
Interpreting all of the driver warnings sent by the control modules on the class 2 serial data line
Sending the information to the instrument cluster in the form of a SPI serial data bus message
The following list of messages are sent by the BCM to the instrument cluster:
• Fuel gauge position
• Temperature gauge position
• Oil pressure
• Low engine coolant
• Check oil
• Volts
• ABS
• High beam
• Low fuel
• High temperature
• Washer fluid level low
• CRUISE
• BRAKE
• SERVICE VEHICLE SOON
• Door ajar
• Seat belt
• THEFT SYSTEM
• PRNDL
Check the fuel level sensor wires , the fuel level sensor is a input to the BCM .

Fuel sender unit could be faulty and showing a full tank all the time. Basically the gauge is a volt meter and the float arm adjusts the voltage going to the fuel gauge when it moves up and down. If it's stuck for some reason it'll show full when it's at the top.

A local garage or auto centre can fix this easily or if you're good with spanners, it's usually located under the rear passenger seat where you can find the access to the top of the tank.

Does the gauge go to zero when you turn the ignition off? If not, then the gauge itself is bad. If it does, then the sending unit is probably bad. The sending unit is inside the gas tank, on the fuel pump mount. Try lifting the rear seat and open the cover plate there to expose the connector for the fuel gauge and pump. Do not disconnect the two hoses! Disconnect it, then turn the ignition key on. If the gauge stays at zero, the sending unit is bad. If it goes up to full, then there is a wiring problem. If you're not familiar with working with this sort of thing, I strongly recommend you take it to a qualified shop.

Could be either one.
You could disconnect the harness at the tank and ground the gauge circuit to see if the gauge will go to full. If it does chances are the problem is the sending unit in the tank.

Could be the gauge on the dash or the sending unit in the tank.

If gauge still shows empty and light is on then inside tank there is a arm thats prob just stuck remove lower rear seat and will see entry to tank gauge has about 3 to 4 screws open and check if arm is down or floating .

There are a number of things that can cause this beeping to happen. Problems in the Air Bag system, Seat Belts, Low Fuel, door or trunk Ajar, Low Washer fluid, Parking Brake on, Going too fast, Turn Signal On, Key-In Ignition, Exterior Lamps ON, Warning Lamp Announcement, or Transmission Over Temperature. You can try the self test to see if there are any codes stored in the computer, if needed.

1. Cycle the ignition key On - Off - On - Off - On within 5 seconds.

2. Count the number of times the Engine light flashes. The number of flashes represents the code. There is a slight pause between the flashes representing the first and second digits of the code. All codes are 2 digits. There are longer pauses separate individual two digit trouble codes.

Well you need a new full gauge kit. It is located inside your fuel tank just behind the passenger seat held down by 2 size 10 bolts.
Before getting a new gauge kit, have you checked all the fuel system wirings and they are OK?

fuel level sensor is part of the fule pump assembly. code is telling you sensor is malfuctioning. do gauges work? if yes i would leave problem alone till you need a fuel pump

The gauge problem sounds like the common issue on the 03-05 Sunfire instrument clusters where the stepper motors on the cluster's circuit board fail over time. It can be fixed, check out this page for more on how to get it repaired - Sunfire instrument cluster fix