Ok, so that 30A fuse RED wire in your pic will be the main power to the converter. Do you have the electronic battery disconnect switch or manual one?..If it is the electronic one then are you really sure you have 12v coming out of it?...thet elecrtonic switch is just a solonoid and even though it is clicking may not be making contact. I would put a jumper wire across the main RED wire in, and main RED wire out and see if the disconnect switch is really working. Your truck charge wire goes direct to the converter so will power up the 12v camper stuff regardless of the camper battery disconnect operation. The 120v converter also powers up the 12v stuff regardless of battery disconnect switch operation. I really suspect that battery disconnect switch as the problem for no camper battery power.
