I have a 2019 kw T680 and the rear speakers are not working. I have made sure the radio is set to 4 channel, no fuses are blown, I couldn't find any switch that turns the bunk speakers off. I don't know what the issue is.
Oh man, you never got a response to this and it's been almost a year. Well I found this thread because my speakers were not working! I was just assigned this truck by the company. What do you know! I had no idea about the two channel 4 channel thing. That was my problem. I hope at some point your speakers got fixed and you're doing great out there.
