How much u bought it and the performance of your car after using it?

that's good a deal good

can share the links ???

is it for diesel engine?   

newbie..haha

Possible causes:
1. fuse blown (check fuse no.10)
2. switch fault (is the orange LED indicator ON when you press the switch?)
3. wiring (if fuse & switch are OK, you need to check voltage at the demister terminals)

1. Not checked yet
2. Orange indicator not lit.
3. Not checed yet

Anyway thanks.

Did you test with ignition key to ON position (demister works only in this position) ?

Do you have a multimeter (volt/amp/resistance) for checking as below?

1. Turn ignition key to ON position  press the demister switch to ON.

2. Irrespective of whether the orange LED is lit or not, measure the voltage at the demister
terminals on the rear windscreen (because it is possible that the LED is faulty).

3. If there is no voltage, then it is likely the switch is faulty. You could replace this switch, or if you want to confirm you could check as follows: pry out the switch from the instrument cluster panel using a (-) screwdriver, unplug the socket.

4. One of the slots in the socket is the 12 V supply, test all against any nearby chassis earth/ground to
confirm one is having 12V.

5. The switch have 4 pins :
  -  2 are for 12V incoming and out to demister - controlled by this switch, zero ohms or infinity ohms.
  -  2 are for the LED supply & earth, always have some resistance

Measure the resistance across two of the pins in the switch. I can't remember which 2 of the 4
pins, just try all the combinations. There will be 2 pins which will have zero ohms when switch
is pressed to ON, and open circuit when at OFF position.

6. If no 2 pins have this ON = zero ohms & OFF = infinite ohms, the switch is  confirmed faulty.

I had same problem too, but (just for the fun of DIY) I sprayed some carb cleaner fluid inside the switch contacts, rinsed with water, checked again; it was ok, so my demister is working again.