My son has a 1994 240 SX with an RB 25 DET swap. The fan of the radiator will run constantly if the fan relay is grounded but I want to return it back to automatically come on at temperature demand. Do not want it running all the time like it is now. When I reconnect that wire back to the relay the fan will not turn on even when the temperature is up to 200°. Could someone please tell me what sensor or switch is responsible to turn fan on ?
I can see two temp sensors..... single tang for the dash gauge, two wire sensor For the ECM. My question is, is the two wire ECM sensor also responsible for telling the ECM to turn on the fan at a certain temperature or is there a third sensor somewhere for that?