air bag systems work on wire resistance, so i would check the scurity of connections and for any water ingress if the carpets got damp. i believe its not a case of black tape as the light has to illuminate and clear for an MOT.
Just a word of warning, air bags can be set off by shorting out connections with a multi meter, yes i had to monitor the discharge current during deployment and one was set off getting a base line reading.
dont lean over the steering wheel when playing with connections