My S1 Pro has a solid red light, even when plugged in. When I unplug the unit from power and the switch is in the off position, the light stays red for about 15 secs. FWIW, your phone support used to be EXCELLENT, now it is HORRIBLE! I've bought your products for the quality and support, but I will think twice about buying Bose in the future. As I type this I'm on my 3rd call trying to get help and I'm well over 20 min's on hold. My last call about this unit I had the same experience, and it took several calls to speak to someone that could actually communicate.
Thank you for joining the Bose Portable PA Community. I'm sorry you're having a problem (red light) with your S1 Pro system.
Is the solid red light on the front, or on the back beside the power switch? Have you done a system reset?
Did that make a difference?
Please watch for a private message.
Bose Pro Community Admin
Have you tried a system reset?
Turn off the S1 Pro System
Disconnect everything (audio, USB connections, Power)
Remove the battery 
Wait 30 seconds
Reinstall the battery
Reconnect (audio, USB, Power)
Turn on the power
I have done the others but haven't tried removing the battery. Mine came with the battery in place. I will check out how to remove it and give that a shot.
Thank you for going through that diagnostic procedure.
Okay, that doesn't sound good. The unit will have to be serviced. I send you a direct message. Look at the top right of the screen for a red dot. Click that, then click Private Messages.
Once I used this forum to report my issues, the service was top-notch. Bose came through again and I much appreciate it. A new unit is on the way to me. Great job!
Jul 20, 2020