Power issue

If it is a Suburban Brand.......no DC needed for 120V AC function (Unless it is a DEL model)

If it is a Atwood Brand ....being a 2004 it needs DC to trigger AC to element



Do the lights work, does the fridge display work, do you have other DC items that function OK........
DOes water heater heat on propane?

If YES.doubt it is a DC issue

Typically it is the element, wiring, t-stat of 120V AC Circuit breaker


But w/o BRAND/Model it is all guessing

Accordingly to a spec sheet it is a DSI gas water heater so begin there to listen for a clicking sound when it attempts to light. No clicking then check power to the control module.

Scott: he may have a pilot light model!
OP: How to you operate the water heater? Do you light it manually or do you turn a switch on?

If it isn't getting 12v it wont work. If it is, it will.

Make and model of water heater?
Do you have winterizing valves? If so verify valves are in the correct possition.
DSI and 120 volt water heaters normally require 12 volts DC for control.

Are you not getting any hot water? If yes, I doubt it would be the converter. The water heater would be the first culprit, the heating element, down to the t-stat the fuse.

Depends. Some water heaters need 12VDC. Standing pilot water heaters dont need anything but propane.