How do you test or fix a 99 Suburban electric window that won't work?
You probably have a broken regulator, and you need to go to a car parts store, and get a repair manual for your car. They cost about $16.00 Or, go to a Public Library.
I struggled with the problem for over a year, I finally determined the electronic actuators just get weak and even though they may work on the bench there is not enough power to drive the locks. Dealer wanted 75.00 each +labor to replace, I found them online for 25.00 and changed all 5 - been working great ever since.