Belts squealing under load - 2015 Corolla 1.3 GLi Auto

[taimurahmed92]

I have a 2015 Corolla 1.3 GLi Auto local assembled car with 32,000 km on it. Lately, I've noticed that under idling when I press all four window buttons down or up at the same time a squealing sound comes from the belts and/or alternator. The sound disappears once I let go of the buttons. Why is the car unable to handle this load? What could be wrong?

[taseensoomro]

Sounds like belt have been loosen.

[mehran]

Belt loose or worn out or some oil or grease on belt or pulley. Can be any of these reasons. You can have tension adjusted or belt replaced. Or avoid opening closing all 4 windows while idling