Fault 1Dxiii. Liveview works.. not ordinary viewfinder view.

This just happened my 1Dsiii body.

Stopped working in ordinary mode. Nothing in viewfinder. LCDs working. No response to shutter button etc. Changed batteries. No good. Several lenses..

yet I've discovered it works fine in Liveview mode.

I messed with it and discovered that the problem is the autofocus. Turn that off and it's fine. Turn it on and it doesn't work.

I cleaned the pins. No good.

Anyone ever come across this fault?