If you have access to the console, you can tell the extruder to extrude manually.
Follow the steps in 3d Print Guide_Walk Through > FINETUNE YOUR SYSTEMSETTINGS > EXTRUDER CALIBRATION. We’re just trying to extrude though, so you don’t need to measure anything or do the calculations (unless you want to - I didn’t need to on my original).
When the print head is in open air, the G1 E100 F100 command should extrude some filament. If that doesn’t happen, there’s something inside the print head preventing the extrusion. Listen for various noises that might give you an indication. I have heard of people that had minor grinding problems getting enough filament dust in the gear that the teeth can’t catch anymore. They dissembled the head and brushed the dust out of the gear.