On my Bus the remote entry module is in the top front of the second compartment on the passenger side. Since my Bus was a special build; we have LP and no Hydra Hot, my first compartment is the LP tank. If yours has that first compartment as part of your basement storage, I'd also look at the top of it too. The control box has a single insulated wire about a foot long just hanging down free from the control box. This is the remote control antenna. I'd check to see if you have power to the box and a signal when you hit the inside button as a start to troubleshooting your problem. A call to Tiffin might also help. I've found them very helpful when I had a problem and didn't know where to start.
2013 Tiffin Allegro Bus 43QGP
2011 Chevy Silverado 1500 Toad