I have noticed a foul smell in my fifth wheel. All sinks have a pee trap, but the shower does not. Is there supposed to be a pee trap installed in the shower?
How old is the camper? And how long has this happened?
If it's relatively new (within the last 2-3 years), there were a batch of Dometic model 300 toilets that were letting pee get between the base and bowl and would stink up the place.