Trimmer won't operate, is less than year old. Connect to cord and won't operate
Try something else (a lamp) in the extension cord. If ok, the case must be opened to expose the wiring. Check for 110-120 volts AC at the cord ends. If nothing, the plug end may have a broken wire. Cut back the end somewhat and install a new plug or just replace the power cord. If still nothing, remove the power connection and ohm-check the switch and motor. The switch should read zero ohms when on and the motor will usually read less than 20 ohms if good. If either reads infinity, replace the switch if so, and check the motor brushes for sticking or bad springs.Hope this makes sense and helps!