Rear Speakers on Clarion radio setup

[Larry from NH]

I recently bought a 2003 21i with a Clarion XMD1 radio. I can't seem to find a way to turn on the rear speakers. My friend who has a newer Tige told me that if the battery is disconnected (which is the case for last winter) for any reason the speakers are automatically cut off. He says to then push the program button (T) and by readjusting the volume the speakers will come on. My XMD1 does not have a program button. Can anybody out there tell me how they handle this problem?
Thank you.

[TigeTrojan]

Check the stereo settings for balance or fade. If the fade is turned all the way to the front, it is like turning the volume all the way down on the rear speakers.