I ran into the same thing on shipping so I made sure I ordered extras (no extra charge on shipping) along with some regular plugs (use them during the off-season because my HR anode stays in a toolbox when not in use and when I'm using propane). Believe it or not, keeping the unit out, is an unintentional built-in "failsafe" mode! IF the electric wh gets turned on inadvertently, no harm done. The HR is a simple circuit of "Continuity" with the unit basically acting as a "resistor". So if it's not plugged in, nothing happens. Note though, my
light will still burn because it's wired onto the thermostat. But then that's another failsafe, if the
light is burning turn it OFF before plugging the anode in! Kinda neat/fun stuff to me.
Now, for clarity, I dont use a
light on the "propane" side. As I state in my album of pics, I use a "breaker" for my HotRod. I completely removed my
propane so now I'm all electric.
So, back to your setup, in order to switch the
lights from the HottRod to
Propane, you will need a little different setup on the switch/lights than mine. You will need to go to a DPDT (Double-pole/Double-Throw switch). It would need to be rated at a MIN. 15A for 120v AC. This would be for the side to carry the HR and power your panel light. When you flip off the HR, it automatically will light up on the
Propane side...and the water heater HR unit will be off.
For what it's worth, you CAN leave the HR in while you use propane. (Shhh, dont tell anyone, but one time I used both when I temporarily installed my propane when I was staying off the grid and using a
generator .) The water heated REAL quick then I shut off the gas and went to my HR with the
generator. (DONT do this with a 3-way fridge!)