To check if your e-collar is working, you can perform a simple test. Most e-collars have a light or sound indicator to indicate proper functioning. Ensure that the batteries are charged or replace them if needed. Then, activate the collar and observe if the indicator light is on or if there is a sound signal. Additionally, you can test the collar by approaching a boundary or using the collar's remote control (if applicable) to see if the dog responds to the stimulation.