9 Tips for repairing iPhone 5

I'm assuming you have tried the obvious things like turning the volume up? If so, you need to replace the ear piece speaker. Link below to buy the part and video on how to fix. Fairly easy repair.
Earpiece Ear Piece Sound Speaker Replacement Parts for Apple iPhone 5C

1.Diagnose the problem with your computer. Watch the screen from the moment you hit the power button through the time it should take to boot into the Operating System. Adjust the computer's contrast and brightness through their full ranges to make sure that the display settings have not been changed. Reset the computer's LCD-External Monitor display with the LCD/External Monitor key combination and reboot the computer. Continue to Step 2 if the screen is blank throughout the booting process.
2.Adjust the screen from its fully closed position to its fully opened position. Watch the monitor for any change from a blank screen to a display or vice-versa. If the screen flashes or cuts out, the LCD panel will need to be replaced. Skip to Step 5.
3.Skip this step if your computer does not have an external monitor output. Connect your computer's external monitor output to a known good monitor and change the display from LCD to External Monitor (the keystroke combination is different for all notebook brands). Reboot the comptuer, if necessary. If the computer does not display to the external monitor, the video card could be bad. Skip to Step 6.
4.Consult with a professional technician to determine the cost-effectiveness of replacing your computer's LCD if you are not knowledgeable in that area. Purchase a compatible replacement LCD and install it yourself, or pay a professional technician to do so if you do not feel comfortable performing the repair.
5.Verify that the monitor connection cables are not loose or disconnected before attempting to replace it. Replace the monitor yourself by removing the old monitor. Remove the hinge covers by gently prying them. Check if they are screwed to the computer before prying. Find the monitor cable's connection to the motherboard. Turn your computer over and remove any plates that may cover the point of connection. Note the orientation of the cables before disconnecting them. Unscrew the monitor from the hinges and gently detach it from your computer. Feed the new LCD panel's wires through the same path as the old wires, and reconnect them. Secure the new LCD's hinges and replace the hinge covers. Power up the computer and check that it works. If it does not, recheck the wire connections.
6.Consult with a professional technician to determine the cost-effectiveness of replacing your computer's motherboard or video card if you are not knowledgeable in that area. Purchase a compatible replacement motherboard or video card, and install yourself or pay a professional technician to do so if you do not feel comfortable performing the repair.
7.Replace the motherboard by disassembling the computer. Document every connection and be sure to retain all screws and small parts in order to reassemble the computer correctly. Reassemble the computer and power it up; check the keyboard to make sure that it has been reconnected properly. Replace the video card by removing any covers or plates that hide the card. Remove the old card and install the new card in its place. Power up the computer to test the display.

1.Diagnose the problem with your computer. Watch the screen from the moment you hit the power button through the time it should take to boot into the Operating System.
Adjust the computer's contrast and brightness through their full ranges to make sure that the display settings have not been changed.
Reset the computer's LCD-External Monitor display with the LCD/External Monitor key combination and reboot the computer.
Continue to Step 2 if the screen is blank throughout the booting process.

2.Adjust the screen from its fully closed position to its fully opened position. Watch the monitor for any change from a blank screen to a display or vice-versa. If the screen flashes or cuts out, the LCD panel will need to be replaced. Skip to Step 5.

3.Skip this step if your computer does not have an external monitor output.
Connect your computer's external monitor output to a known good monitor and change the display from LCD to External Monitor (the keystroke combination is different for all notebook brands). Reboot the comptuer, if necessary.
If the computer does not display to the external monitor, the video card could be bad. Skip to Step 6.

4.Consult with a professional technician to determine the cost-effectiveness of replacing your computer's LCD if you are not knowledgeable in that area.
Purchase a compatible replacement LCD and install it yourself, or pay a professional technician to do so if you do not feel comfortable performing the repair.

5.Verify that the monitor connection cables are not loose or disconnected before attempting to replace it.
Replace the monitor yourself by removing the old monitor. Remove the hinge covers by gently prying them. Check if they are screwed to the computer before prying.
Find the monitor cable's connection to the motherboard. Turn your computer over and remove any plates that may cover the point of connection. Note the orientation of the cables before disconnecting them.
Unscrew the monitor from the hinges and gently detach it from your computer. Feed the new LCD panel's wires through the same path as the old wires, and reconnect them. Secure the new LCD's hinges and replace the hinge covers.
Power up the computer and check that it works. If it does not, recheck the wire connections.

6.Consult with a professional technician to determine the cost-effectiveness of replacing your computer's motherboard or video card if you are not knowledgeable in that area.
Purchase a compatible replacement motherboard or video card, and install yourself or pay a professional technician to do so if you do not feel comfortable performing the repair.

7.Replace the motherboard by disassembling the computer. Document every connection and be sure to retain all screws and small parts in order to reassemble the computer correctly. Reassemble the computer and power it up; check the keyboard to make sure that it has been reconnected properly.
Replace the video card by removing any covers or plates that hide the card. Remove the old card and install the new card in its place. Power up the computer to test the display.