If you can look at the backside of the water heater, see if there is a regular white 14-2 residential style electric cable going into it somewhere. If there is, there should be an on/off rocker switch somewhere on the back of the heater. Make sure that is set to OFF.
If it is a 110vac/propane heater, there should also be be a separate circuit breaker for it in the main electric panel. Make sure this is set to OFF.
My last trailer had a Dometic heater and looked like this:
You can clearly see the white 110vac wire entering the top of the heater at the blue strain relief. The on/off switch is to the left of it and is that thick black line with a piece of white foam on top of it. The Suburban heater will similar in appearance.
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'11 Cougar 326MKS loaded with mods
'12 Ford F250 SuperCab 6.7 PowerStroke Diesel
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