Disconnect the power to the effected device. Even with low voltage DC circuitry, the power should be disconnected before electrical parts are serviced. Disconnect the power by pulling the fuse to the affected circuit, or pulling the negative lead from the RV battery.
Remove the defective part from the RV. Switches can be removed by simply using a screwdriver. Electrical motors and servos may need to be disconnected from the electrical system, then unbolted from the RV's frame
Do not cut any wiring as the device is removed. RV switches, servos and motors are attached into the electrical system with custom molded electric pigtails and fittings. Detach the wiring at the pigtail.
Test the part with a VOM to verify it is defective. Switches should close a circuit and allow voltage to flow through them when they operate properly. Motors and servos, when direct-wired to a 12V DC power source, turn on. Use a VOM and an external power source to verify the item is defective.
Contact a local RV repair facility/dealer. Inform them of the make, model and year of your RV. Source the replacement part from a certified repair facility, then install the new part using the same steps, in the inverse order it was removed.