What can I tell you. Its a light bulb. You put it into its intended socket and apply electricity and hope it lights up. If it doesn't after you try said new light bulb then something else is probably broken, But since you bought a package of 2 you might as well try the other one just to make sure the first one wasn't defective. Maybe that's why they come in packages of 2. I suspect however that the real reason for packages of 2 is that the manufacturer wants to sell more than what you actually need to fix your problem or possibly a spare one you will inevitably loose anyway. Therefore when you need another one somewhere down the road you won't be able to find the left over one from before so you'll buy 2 of them again whereby repeating the whole buy one loose one cycle. So to recap and most importantly it's a light bulb. It emits light if operating correctly and is most likely broken if it fails to do so once a reliable electrical supply has been established to said light bulb receptacle. Secondly, be prepared to most likely buy twice as many of these than you will probably need.