No - there is no hitch or wiring for towing of any kind.
We can't tell exactly when it does blow - all we know is that the directionals will work for a few hours and then when you try them again, they don't. Upon checking the fuse, we find it has blown.
Yes - I checked and no other fuses have blown. Correct - the fuse that is blowing is the fuse that is located in the PDC under the hood.
I think I may have found the problem this morning. In frustration I pulled out the PDC altogether to test the socket to see if there was a problem there. When I turned over the PDC to find the correct pin to check, I found that the pin itself below the 20A fuse was loose and wobbly. No other pin on the entire board moves at all. I'm thinking that perhaps this pin moves when the car moves over pavement bumps and that momentarily increases resistance to the point where the fuse blows.
I've ordered a new PDC - 450 bucks - and hope that will resolve the issue.