2001 Tahoe LT Questions

[Cooper33]

I have several questions: The idle seems low, around 500 rpms sometimes less, mainly effect the efficiency of the A/C, is there a way to increase the idle? Also, ABS pump was humming after engine was turned off, I removed the fuse, but need to repair. what needs to be fixed? the controller on top? the pump it self? Last but not least, the rear passenger windows, seem to go down but won't go up. Do i just need to replace the motor? Or is it something else? Thanks for your help. The Tahoe is my daughters and has 158k miles with 5.3 engine.