There are many reasons as to why your gas grill isn't lighting. Make sure to check the burners, ignition battery, electrode wires and the propane tank.
Check the burners
Check that the grill burner is engaged with the control panel, and make sure your valves are positioned inside the burner tubes.
If your grill won't light, it could be because you're lighting the wrong burner. See instructions on the control panel of your grill and in your manual.
The grill burners could be blocked if your grill doesn't light. Pests, spider webs or other debris could be blocking them.
Check the battery
Make sure that the ignition batter is not dead. If it is, you'll need to replace your igniter battery
Make sure the battery is correctly positioned. Follow your manual instructions
Check to make sure that the battery electrodes are not wet, oxidized or slightly corroded. You may need to remove battery and clean off electrodes with dry cloth or with alcohol wipe. Reinstall battery.
Check the electrode wires
Make sure that the electrode wires are connected properly. Reconnect the wires or replace the electrode wire assembly
Make sure that the electrode tip is in the right position. The electrode should be pointing toward the gas port opening on a burner. The distance should be 1/8 inch to 1/4 inch. Adjust as necessary.
If your grill won't light, it could be because you have dirty electrode terminals. Clean them with rubbing alcohol and a clean cotton swab.
If your grill is not lighting, are you seeing sparks at your electrodes? If so, you may have a damaged electrode. You will need to replace it
Check the propane tank
Make sure the propane tank is connected to the grill properly. If your grill isn't connected correctly, you could have trouble lighting it. Make sure the coupling nut and propane tank cylinder valve are fully connected. Turn the coupling nut approximately one-half to three-quarters additional turn until a solid stop. Tighten by hand only. Do not use tools or you could strip the threads.