They used that song by La Banda Gorda ad-nauseum. Since the OP mentioned hearing "trabajando" as one of the words, that has to be the song.
The words are: dejen esos perros que sigan ladrando, eso es se?al de que estamos trabajando. The PLD took on that phrase as a motto during their campaign.
Sorry, Hipocrito Mejia, I left the smiley out of my post. The reference to Amnesia was because of the Governmental austerity programme last time round.................ok, I won't give up the day job for political satire :cheeky:.