Radiator fans not working

It started off getting hot in idle but would cool off once accelerating but ended up blowing head gasket. Going to put blue devil sealant in it and try to fix it. But my question is about the fans. It has got two fans on the radiator and it’s not working or kicking on. I believe one runs off the belt and the other runs off relay. I changed the thermostat and the radiator fan relay and it still isn't kicking on. What else could it be? The heat has never worked in it, but it blows it just don’t get hot. What are some things I could do or check? Please hit me back. Thanks