2003 Yukon XL Amp Replacement

[twita7]

I recently purchased a replacement OEM Bose Amp 15054674 (on ebay from LKQ - certified condition A) for my vehicle as I did not have sound in either middle door or rear speakers on both sides. After changing out the unit, I now have rear sound on both sides and subwoofer yet still don't have middle speaker sound on either side. The middle speakers have been checked to have good continuity. Any suggestions?

Thanks in advance,

Kory