Key FOB for 2000 Passat quit responding
 

I have a 2000 Passat that has the flip out key built into the FOB. I just replaced the batteries 2 days ago, which gave me better range, but today, nothing. No trunk release, no lock/unlock function. Before this occured, I noticed that the horn that confirms each push sounded more like a clown car horn. I do believe it is different than the horn on the steering wheel, as that one sounds normal. I pulled every fuse from the side panel on the driver side, all are fine. The door panel controls all seem to work properly from the inside, but there is no response from the FOB. Any thoughts on the next step?