speaker connection

I noticed 4 speakers on the ceiling of my 91 terry trailer model 18d. I unscrewed them and tried to follow the wire but For the life of me I can't find the speaker hookup for the speakers. Does anyone have any leads or resources on how to hook these speakers up other then ripping down the walls...

Getting power to Jensen radio, dvd player, etc. Have checked speaker on/off button on actual radio and it shows speakers are on but I am not getting any sound. I am usually very good with electronic devices but I have read the entire manual and feel the problem is with the speaker connection...