Always stay calm!

A failing light bulb is of course some reason to panic, especially if you don't have a clue about anything mechanical, but I can talk you through this repair!

Won't cost much more than 15 minutes, maybe 20 at most!
My list of Xantia troubles:
broken clutch cable thingie (to be towed home with a 2cv that couldn't go uphill with a xantia on a rope behind her..
Broken clutch cable (a CX turbo to the rescue: that was not issue but it was a long trip in the dark..)
A badly leaking anti sink whatever (got home on the handbrake...

)
2 times broken linkage of height corrector)
broken exhaust clamp (rotted through) came home with ever body looking odd
Twice engine running on 3 spark plugs (you really should change them regularly!

Frozen grease in a drive shaft gaiter causing the steering to almost fail during the big freeze winter and being abroad. Gaiter wasn't broken at all!
Failed clutch bearing - home on a recovery truck, thankfully at work when it happened.
Broken door hinges (twice)
Rotted wires in the wiring loom underneath the radiator. Causing me to buy an even more rotten xantia which is a longer story of failures..

Anyway out of action for 3 months..did get home with it thankfully.
Broken thermostat wiring - fans wouldn't kick in no matter what I changed/built over from the other xantia (wiring - fans - etc.etc.)
Failing starter motor - just where it was dangerous...
Broken window cable...
A broken petrol pump - towed home with the other xantia.
A rotten spark plug thread - swopped head from earlier xantia just before -
a mysterious leak caused by sunroof drain...figured out soon enough but not before my guests got quite wet (always check your back seat)
a failed dasboard bulb I never bothered to fix and
and than finally a serious rot problem in the wiring loom (or was it a mouse..)
The rest I've forgotten for now, but you do have a serious problem but it can be resolved Jim

I even have a spare bulb for you if you so wish!