There is a strange problem with my lightings stick (Not sure about the exact term, but please refer to the attached picture) in my Citroen C5 2007 2.0 Petrol.

Headlamps are working but fog lamps not lighted up when switching on and off using the stick. When I did my electrovalves change recently, the Citroen service centre told me briefly that both front and rear fog lamp are working. Just that the stick to switch on and off is not working.
They told me I have to change the whole stick to make it work again and quoted me a bomb for it.
What could have been the problem? Is there a more economical way to solve this problem?
Kindly advise me.
Thank you very much.
Regards,