How to say “The exit sign over that door has been flickering since Monday.” in Japanese

In Japanese

あのドアの上(うえ)の非常口(ひじょうぐち)サイン、月曜(げつよう)からずっとちかちかしてるよ。

ano doa no ue no hijōguchi sain, getsuyō kara zutto chikachika shiteru yo.