Vents stop producing air flow

Hello,

Just to clarify, after a minute the blower motor slows down in speed.

This could be due to a bad blower motor resistor. The resistor controls the speed of the fan. A faulty resistor can have excessive internal resistance when it warms up and slows down the fan speed. It can also be a malfunctioning motor.
The blower motor is located under the passenger side dash. The resistor is mounted on the blower motor housing (see diagrams below).

https://www.2carpros.com/articles/blower-fan-motor-works-on-high-speed-only

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.