If the sun roof works, the problem isn't circuit breaker or relay.
I'd get at the wiring harness on hinge side of driver door, probably has a protective covering, pull the covering back so you can see wire colors. Brown is voltage for power windows, black is ground.
According to my database, the sun roof and power windows use the same circuit breaker and relay. Your owners manual should give you the location of circuit breaker and relay, I just looked at your owners manual, it just said sun roof for the relay, but, power windows work off same relay.
If you don't have an owners manual, you can read one for free online, at
www.my.gm.com
You'll have to type in year--make model.