Almera 1.5 2004

Nissan Almera accessory drive belt is located on the front of the engine. The cooling fan is most likely not driven by the belt as most all cars now use electric motors for the cooling fan. The belt will be driving the alternator, so find that and you have the belt in sight.

Find the fan relay, resistor, and fuse check all for proper function. If it all in good order start looking at failed wiring.

Turn the heater tap to hot setting.

doubt it --- for sudden problems check items like fan operation if electric, viscous fan hub if fitted, blocked radiator fins / corroded fins, failed cat converter blocking exhaust.
run the fault codes to check for any sensor failure.

Are you talking about engine radiator cooling fan?
If yes there is no switch per say, the fan is connected to a relay and gets activated by the temperature sensor of the coolant, if it is not coming on check for a blown fuse or a bad relay.
If you want to test the fan, connect the fan straight to the car 12V battery and see if it is working.
Make sure that your hands are not close at any time to the fan blades, and don't wear any kind of loose clothing and jewelery.

one switch will do the job

i r&r atleast 20 to 30 blower motors a month and about 85 % of the time the motor has just givin up due to normal wear and tear, and a combination of diferent obstructions, simply cleaning out debris and attempting to fix isnt the solution, blower motors are cheap, and most can be removed& replaced in under 5 minutes

That noise is the heater and AC air temperature control electric blend door motor trying to move a duct door that is sticking due to heat warping. You will need to remove the entire dash assembly and replace the blend door. This door is located between the AC core and the heater core and "blends" the air from each (hot from heater core and cold from AC core) to give the desired air temperature,.

renew the bulbs

Hi there, very common on these vehicles, you need to remove the heater cotrols and check that the cable hasn't come out, usually the clips that hold the cables in place break causing the heaters to not work properly, Nissan do modified clips now to stop it from happening, it may need a cable too if its too far bent, hope this helps.