Instrument cluster does not work

Hey, everything was working perfect except that my car had an airbag light due to an accident. I replaced the airbags a month ago but still I had to replace the seat belts since the front seat re-tractors were locked. So, yesterday I received my seat belts and after installing the seat belts, immediately after starting the car the instrument cluster gone blank, no lights, no gauges, no warning signs, everything in the cluster stopped working. I later on realized that even the power windows, sunroof and reverse lights stopped working also. I checked the fuses and to my knowledge they all gave me continuity. My question is, what could be the issue to this problem? Is there like a module that controls all these parts or a relay that I am not aware of? Your assistance will be greatly appreciated!