It is located behind the center console near the accelerator pedal and is held by 2 screws.
maybe check the thermostat.
Behind the glove box, upper left hand sorner above hose. 2 screws holding it in place.
it the brown relay in the passenger side relay box
probably the resistor pack on the evaporator case.
Blower resistor switch
The cooling fan relay for a 2002 Nissan Sentra is typically located in the engine compartment, within the fuse and relay box. This box is usually situated near the battery on the driver's side. To locate the specific relay, refer to the diagram on the cover of the relay box, which will indicate the position of the cooling fan relay. Always ensure the engine is off and the key is removed before accessing electrical components.
Maybe it's defective, maybe an electrical connection came loose, maybe a relay or fuse was blown.
the black relay box under the hood on the passenger side. next to the windshield wiper fluid
Your blower motor is on the passenger side of the engine bay mounted on the firewall. It should be just a couple of screws and a wire connector to deal with.
Short in the speed control switch or the wiring.
The Nissan uses a series of resistance wires to change the speeds on the blower motor and this unit can be found in the heat box right near the fan motor. It is in the airstream after the fan to allow cooling of the resitor wires by the air produced by the fan
No. One fan is for the radiator, and the other is for the condenser. If you have the A/C on, they should both be on. Else, just the one for the radiator, if the thermostat is open.