Check out the fan control switch, I can't remember whether it's on the
radiator or on the thermostat housing on that engine, either way it's easy
to see and easy to get to, just bridge it out with some wire and see it the
fan runs (ignition on)
If you do swap the switch, don't go mad with the big spanner 'cos you'll
strip the radiator tank/thermostat housing and end up wanting new ones of
them as well.