Hi, here are some things to check:
If you have a 12 volt test light, connect the test light to battery positive and probe the black wire with a brown stripe at the fan connector. The light should light, or you need to repair the ground connection.
Start the car and let it heat up. Then, assuming your horn works, borrow the horn relay to check the fan relays. Mark it so you know which one is good. Put the horn relay in each of the 3 fan relay sockets, one at a time, leaving the other relays in place. If putting the horn realy in any of the fan relay sockets works to turn the fans on, leave it there and buy a new relay for the horn.
If this does not work, pull out the fan high relay, start the car again (engine still hot) and probe the relay socket with your test light. Terminal 85 should light the test light.
If still no-go, you will need a voltmeter for the next test. Leave the sensor connected and use the voltmeter to probe the back of the coolant temperature sensor. Check the voltage on the sensor wires with the engine running. The reading should be between 1-5 volts DC. If not, replace the sensor.
If none of this works, consider replacing the front control module (in the same box as the fuses and relays).
Please let me know if you have questions, and thanks for using FixYa.
coolant temp sensor location: