How do I troubleshoot a non-functional heater in my Audi A2?

My Audi A2's heater is not working, and I'm having trouble figuring out the issue. What steps should I take to troubleshoot and resolve the problem?

First, check if the heater blows cold air or if there is no air coming out at all. This could indicate a problem with the heater's fan or motor. Try turning the heater on and off to see if it responds. If it doesn't, there may be an issue with the wiring or controls.

Next, check the coolant level in your car. If it's low, this could be the cause of your heater not working. Top it off if necessary and see if that resolves the issue.

If the coolant level is fine and the heater still doesn't work, it could be a problem with the thermostat or heater core. These are both components that regulate the temperature of the coolant and can affect the functionality of the heater. It's best to have a professional mechanic inspect and replace these if necessary.