Solar lights use a small photovoltaic panel. When the sun shines on them, electricity is generated, storing power in a small battery bank. When a solar lights fails to light up, there are a couple of reasons for this. It only takes a few minutes to get your lights up and running again.
Unscrew any screws on the underside of your solar light.
Remove the glass. You may need to unscrew the glass to remove it.
Clean the glass or casing in hot, soapy water.
Locate the batteries under the top of the unit.
Remove the battery cover, if there is one. You may need to unscrew this.
Clean the battery ends and terminals. You can remove any rust or corrosion with sandpaper. Remove any bugs and dirt.
Test the batteries with a battery tester or a volt meter on a low DC setting. If the batteries are fine, it is probably a faulty photocell. The photocell is a light sensor that controls when the solar lights turn on or off.
Remove the old batteries and replace with new ones, if necessary. You will need to place the solar light in direct sunlight for at least two or three days to charge the batteries.
Place black electrical tape or duct tape over the photocell at night. If the light comes on, the solar light is probably too close to other light source.
Remove the other light source, or keep the black tape over the photocell, but only partially. This will still allow some of the light to come in.
Be sure that your solar light is placed in a location where it will receive 8 hours of sunlight per day.