First answer, get a Haynes. Book 5558, covers Panda and 500, has a description to remove fascia from page 11.32. It starts with the paragraph: "Note:This is an involved operation entailing the removal of numerous components and assemblies, and the disconnection of a multitude of wiring connectors. Make notes on the location of all disconnected wiring, or attach labels to the connectors, to avoid confusion when refitting."
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Subsequent operations refer to various sections of the book, for removal of airbag, steering column switches, and radio etc.
Why?
Has the airbag gone off? If it has, was this caused by carelessness with connections, a faulty airbag, or a collision?
If carelessness, good luck fixing it.
If a faulty airbag, I'd be asking Fiat to contribute, regardless of vehicle age.
If a collision, for the airbag to have deployed, I'd also expect significant frontal impact damage, including chassis damage, and any seat belt worn at the time will need replacing too. Is there more to this story?