In photo 2 it looks like the red connector is for an option that you might not have. It may drive a micro-switch to break the flow of 12 volts. Like when you open your door the step light would come on, or a switch to control a lamp in the electric compartment... could be a lot of things.
in photo 3, the white 4 pin modular connector is very common in RV components. Usually the connector connects to a pc board the contains a 4 pin bosch style relay. The white wires will have a signal printed on them to give you the idea of the what circuit it is driving.
in photo 4, the black connector is where you would plug in a Bosch style relay. You would have to look at the back and see what signal wires are there to determine what the relay is for. Could be something like daytime driving lights that are not needed in US but are there for Canada.
in photo 5, that looks like a connector for your electronic brake controller. Is your motorhome wired to tow a trailer?