Engine cooling fan

Try the cooling fan switch, it looks like a large brass nut with wires on it on the thermostat housing or radiator.
To test, pull off the wires and connect together, turn on ignition and the fans should cut in.
If they don't it could be the relay, fuse or broken wire.
The switch is easy to replace, unscrew and rescrew in the new one. Connect the wires, not important which way the wires go, and refill coolant.