COOLING FANS WONT CYCLE

[jbmeyer2001]

I HAVE A 1997 SENTRA GA16 THAT THE COOLING FANS WONT CYCLE THEY DOT COME ON UNTILL ENGINE TEMP GETS UP THERE THIS IS NORMAL BUT THEY WONT SHUT OFF TILL YOU CYCLE THE KEY TO THE OFF POSITION THIS CAR HAS HAD AN OVER HEATING CONCERN THE HEADGASKET HAS BEEN DONE ALONG WITH RADIATOR AND WATER PUMP AND T-STAT ALSO COOLANT TEMP. SENSOR SWAPED RELAYS AND SWAPED ECU'STHANK YOU FOR ANY HELP YOU CAN PROVIDE ALSO IAM A TOYOTA CERTIFIED MASTER DIANOSTIC TECH , ASE MASTER WITH L-1 AND THIS ONE HAS ME STUMPED
Modified by jbmeyer2001 at 6:31 PM 4/13/2007

[gonnabeturbosoon]

well first i would look at the fsm for your car and it will tell you exactly how to fix it. Although, usually the cooling fans all have a basic system. First there is a fuse, then a temp sensor, then a relay maybe and finally the power is sent to the cooling fans. I would back track. If the fans come on you know that the fans and fuse work. I would check your relay or thermostatic sensor. One of the two could be going bad. I would take the relay out if equipped and change it with another off the car that has the same color. Try that and see if works. Plus if you have a meter you can probably the temp sensor by heating it up and the sensor's ohms should raise or lower, something like that. I would consult the fsm for the proper way to diagnosis try a chiltons or haynes

hope that helpsaricanderson

Here is some info on a 96, i didn't find the 97



Cooling fan sensor. Is located in bottom hose tee of radiator. Drain the coolant from the radiator. Remove the hose tee and place in a vise. Remove the sensor from the tee. Apply thread sealing tape to the threads and torque to 15 ft. lbs. (20 Nm). Some late model vehicles have the sensor threaded into the radiator tank. Be careful not to damage the radiator threads when removing.


Modified by gonnabeturbosoon at 3:26 PM 4/13/2007

[RICERMAN]

Maybe the engine isnt cooling down enough for the fans to turn off. Are you sure the engine is running within the normal temp range?You need to inspect the complete cooling system for leaks.or malfuntions before you know for sure there is a problem with the fan switchs.If the fans just wouldnt turn on thats one thing , but I suspect you may have a cooling issue. good luck

[240sxmech]

possibly the relay is sticking on when energized from the ecu and only resetting when you cycle the key off , suggest swapping another relay.If that doesnt work then take a temp gun and shoot the thermostat to check your temps.

[jbmeyer2001]

this problem was fixed by replacing the aftermarket stat with a nissan stat the fans work properly now thank you all for your help