Having outdoor solar bollard lights is a great idea because they are easy to install, flexible to be placed around and do not require electrical outlets. But these units might have issues over time and stop working. Fortunately, you can easily deal with such problems.
Check the Lights
Check to see if its switch is entirely on. Perhaps the switch is under the cap or light capsule. In such a case, loosen the cap by turning it counterclockwise to access the switch. Once you set the switch on, place your garden solar light in an open space with full sunlight. To test this, cover the panel with your hand. Another cause of an unworking garden solar light is the buildup of moisture inside, corroding the electrical connection between the unit and solar panel. Check for any sign of rust and replace it if necessary. Make sure to check the wiring and see if it is still in good condition. Sometimes mice can gnaw through the cords. Use electrical tape to fix it.
Revive the Panels
Another reason your solar light is not working is a dirty plastic cover. This is a common issue for many cheap units. If it still looks cloudy after wiping it down with a soft cloth, apply a coat of nail polish once it dries completely. This might help your solar panel receive sunlight again and charge the lights as usual.
Inspect the Surrounds
A garden solar light may stop working just because surrounding trees have grown and blocked most of the sunlight. The solar panels will not get sufficient power to charge the unit. So trim back any overgrown branches or move your lights to another space that receives direct sunlight. Maybe your garden solar lights or their panels are not facing the sun directly due to thawing. Put them back in the right position to maximise the light received. Wipe any dust off the panel with a soft cloth. After getting light for a few hours, the units should illuminate as usual.
Examine the Batteries
If you have tried all the solutions mentioned above but your garden solar lights still do not illuminate or charge, chances are you need to replace the batteries with rechargeable ones. As the batteries are often located under the panel assemblage, open the compartment with a small screwdriver and check the interior. Make sure to replace with the same type of batteries.