E750 touchpad buttons not working, even after replacement

Im stumped so im reaching out, i have a E7450 which the touch pad buttons do not work on. I reloaded windows, and even used a lived USB and the left and right buttons do not work. If i plug in a external mouse i can click and right click just fine. I was thinking hardware but the on-board diag shows everything is working. I got another top plate thinking the actual buttons were bad and that doesn't work. I've even replaced the keyboard and the buttons on the keyboard also do not work. At this point im thinking motherboard but its odd nothing else is having function issues, all wifi/bluetooth  etc are working as expected. Ive also reset the bios, and reinstalled the lastest touch [ad drivers. Again the touch pad itself works, just not the physical buttons.  Anyone have thoughts on what might be the cause?