2007 Audi A8 Quattro Q&A

2007 Audi A8 Quattro Question: How do I troubleshoot my rear window defroster?

When I press the dashboard button for the rear defroster, the light comes on and, the outside mirror defrosters, which are also controlled by the same switch, begin to defrost. I have no indication the rear window defroster is working no matter how long I wait. I don't see a fuse specified in the owners manual. Can anyone help me with this? The window grid appears to be intact. -
Answer 1
maybe there is no power to your defroster -
Comment 1
this reply states the obvious. the question is how do i troubleshoot it? -