12Volt problem

[oddjobal]

2012 295RK. When turning on any inside light, or awning switch my DC Voltage drops to 7.5 v. 2 lights and it is under 5v. Slides, stab. The entire 12v section up in the front compartment seems it be constant battery voltage. Battery has been checked. Switch panel has been checked for loose wires and every connection is tight. Disconnected (1 at a time) wires going to the fuse block. Removed each wire 1 at a time, turned on a light and watched the voltage drop. Hoping to find 1 circuit causing the problem. I am starting to think it may be the converter. I can not think of anything else that is common? Does any one know where they hide the converter. I am using clip on lights that work on 120v. I am open to suggestions. The lack of information from Keystone is surprising.