Radiator fan stopped working

Your car uses a coolant temperature switch to turn on the radiator fan relay. That switch has a single wire plugged onto it. It is a light green wire. Unplugging that switch would turn on the radiator fan by default on newer cars, but on yours, that wire must be grounded to turn the relay on. If the fan runs when you ground that wire, the rest of the circuit is working and the switch is suspect.

If the fan does not run when the switch is grounded, start by checking the 30-amp "radiator fan" fuse link. If that is burned open, the common suspect is the fan motor has tight bearings. Replace the motor, then the fuse link.

If you hear the fan relay click when you ground the light green wire, but the motor does not run, check for twelve volts going to the motor on the black/red wire. If you have it there, check the ground wire for continuity. If that is okay, suspect worn brushes in the motor.

If you do get the fan relay to click, but there is no twelve volts to the motor, suspect arced contacts in the relay.

You grounded the fan wire or the wire to the coolant temperature switch? If you grounded the wire at the switch, and the fan turned on, the switch is defective or there's a bad connection on that connector terminal. The switch is likely to have a low failure rate, so I'd be happy with a used one from a salvage yard.

Everything else worked, so either the switch is defective or the terminal in the connector isn't making good contact with the terminal on the switch.

Do you hear or feel the fan relay click?

Tell me your exact year, model, and engine size so I can look for a diagram. For now, look for a fuse labelled for the radiator fan and check it. I suspect you should find two tiny holes on top of that fuse for test points. Use a grounded test light and check for 12 volts on both of those test points. If you find 12 volts on just one of them, that fuse is blown. Electric motors draw very high current when they are forced to slow down, as in when they have tight bearings, so the motor is the best suspect if the fuse is blown. Spin the fan by hand. It should coast a good two or three revolutions. If it stops right away or is hard to spin, suspect you're going to find the fuse blown.

I'll be back tomorrow to see what you found.