Radiator Fan

 

Can anyone advice what could be the problem with my 1997 Elantra radiator fan which only works when the air-conditioner is put on???Its supposed to work when the engine has reached a certain temperature automatically. My engine recently almost over-heated because I had the air-conditioner off and did not realise that the temp-needle was heading to the danger zone. Could it be the sensor in the radiator pipe has gone bust. Any help will be appreciated.

IT IS YOUR TEMP RELAY