I read your question 3 or 4 times but I am not 100% sure what you want to do. What is the relay going to be used for? Do you want to power the CB with the relay, the fridge or the entire circuit?
Do you want the existing switch to control the relay?
You don't inherit the world from your parents, you borrow it from your children.
1979 Unimog 416 Expedition Camper
1974 Unimog 421
2004 Dodge Ram 2500, 4x4, Double Cab, Cummins Turbo Diesel
2006 25' Airstream International CCD
2009 Harley Davidson
Sugarloaf, Boulder, CO