Suburban Water Heater SW6DE? There's a tag in the right side of the frame inside the cover door.
Our Jayco has what looks like a residential wall switch but with an indicator light. And the Light is ON when the Electric side of the Water Heater is ON.
If it's working the opposite - Indicator ON when Heater OFF, I suspect the Indicator is miswired.
The Electric feature IS working, right? I ask because if it's SW6DE, Suburban tucked a switch into the left side of the heater's panel, again under the cover door, but hidden behind another part.
If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB