Something is shorting that side. Don't connect it until it's found. You could damage the unit. Do me a favor, and this is going to sound crazy. Disconnect the speakers that are not working. Connect two wires to the connections on the speakers. Next, take a double A battery or a 9 volt and while holding one wire on the battery --. Take the other wire and tap it on and off the battery +. If the speaker is good, you will hear it respond to the battery power. It should make a clicking sound. If it doesn't, the speaker is shorted internally and needs replaced.
I realize this sounds archaic, but it is a simple way to determine if a speaker is blown.
Let me know what you find.
Joe
Sunday, January 12th, 2020 AT 5:03 PM