How to troubleshoot a non-functional blower motor in an Audi 80?

I recently noticed that the blower motor in my Audi 80 is not functioning properly. The air coming out of the vents is weak and inconsistent. How can I troubleshoot and fix this issue?

First, check the fuse for the blower motor. If it is blown, replace it with a new one and see if the motor starts working. If the fuse is not the issue, then it could be a problem with the blower motor resistor. Check for any signs of damage and replace it if necessary.