In my previous Lance, a 2001 model, I found out the hard way that the water was getting into that compartment from underneath the rig. The rear truck tires were throwing the water off the highway up onto the area behind the tires. I ended up with major wood rot, behind the metal and had to rebuild the entire corner. What I found in taking it apart was there was no sign of any caulk on any of the underneath seams. I had been very diligent about going over the upper seams, windows, lights, etc. every six months and recaulking as needed. Never once thought about the need to check under the back of the TC.
http://pajbcooper.com/Lance%20Camper%20845%20Repair.htm
