CECarey,
The OEM water heater in your trailer was a Suburban brand "tank type water heater". It was a "dual source water heater" that could operate on either/both LP gas or 110 VAC. There was a 36K BTU LP burner and a 1100 watt electric element.
THE OEM WATER HEATER IS NOT WHAT YOU POSTED...…
The photo you posted is a "LPG ONLY" demand water heater. Apparently the previous owner replaced his OEM water heater with the Girard-GSWH-2. It will only operate on LP gas and does not have any 110 VAC capability. Even if you find an electric switch inside your RV, it was wired to the OEM water heater, not to the Girard-GSWH-2.
You can read about your water heater at this manufacturer's link:
https://www.girardgroupcompanies.com...ater-heater-47
As a note, the Girard-GSWH-2 has a 42,000 BTU burner input, so you're correct when you say that it "burns through some propane"... It's "energy efficient" in that it only heats water when there is a demand for hot water, but "my goodness" it uses a LOT OF PROPANE while it's producing hot water !!!!!