[Daryles]

Without a diagram (which Keystone will not provide) I'm guessing. You would need a multimeter to Ohm out the wiring and create your own diagram.

I believe the 5A fuse is in line with the relay.
The Electric wall switch turns on the relay.
The relay controls the 120vac which goes to the element.
There is a 15A circuit breaker in your circuit breaker panel that is for the heating element. .
The Electric side is very simple and straightforward. The wiring diagram in the Suburban manual doesn't tell the whole story unfortunately.

The GAS water heater switch goes to the water heater control board which runs the propane side of the water heater. Much more complicated due to the safety involved with propane.