once i had a similar problem that 2 of the 18 blubs stopped working and the bulbs need changing was very obvious so i went to the dealers and around the dealers to find the replacement bulbs the dealer price for 1 tiny bulb was 200 and if i get it outside 160 to 140 which blew me off so i let all of them get fused went to scrapyard got entire 18 blubs for 400 aed and replaced them.