Fan problems

[kosteniuks17]

Hey so im not sure what engages and disengages the fans behind the radiator. But ive been gone for two weeks and noticed now that the fans dont run at all when the engine is on. Both of them turn on when i press the ac button, but I drove it on the highway for like 15 minutes and the fans never turned on when i got back with the ac off. Is it because its colder outside. I sware i remember them especially the one right in front of the header always on when i turned on my car. I just replaced both of them like 8 months ago. Why would they both turn on when i hit the ac button but not be on when my engine is running. Please let me know im planning to do a lot of driving this weekend and dont want to overheat or something.

 

[kosteniuks17]

I just thought about it, you think it would have anything to do with the homeade resistor thing for fixing the ac flickering for the light? I know fans know when to turn on by voltage readings. Maybe that how to tutorial thing for fixing the ac flickering switch fixed the ac light but is now causing problems with my fans. The resistors might be causing the fans to be misreading the voltage and therefore not turning on. Idk what do you guys think?

Or does our cars use a temp. sensor to turn on the fans?

 

[whatusername]

no they both turn on when u turn the ac on cuz thats what they are supposed to do. the left one is the rad fan and the pass one is the ac condenser fan if either of those was not on when the ac was on u would most likely over heat..
Now with the ac off only the rad fan comes on but it is not always on it only turns on when the car reaches a certain temp. then it turns off when the temp is lowered. i dont know the act temp.
what controls that fan is a relay in the relay box on the drivers side.. pull it out and re seat it and let the car idle and see if fan comes on by itself if not replace the relay

 

[808MP5]

The radiator fan turns on at around 90c and turns off at around 88c

When I was running obdii + scan gauge the fan would kick on at 204f and shut off at 195f. Ur fan shouldn't come on at highway speeds unless chugging it up hill.