IF it is a Suburban water heater. As noted above, there is a black rocker switch on the water heater itself, outside, behind the water heater grill, at the lower left hand corner of the water heater. Make sure that switch is on. Some units have a second switch on the inside wall panel. My 2007 does not have the inside switch and I have to always go outside and actuate the outside switch.
If the switch(es) are on and it still does not work, then if you are comfortable troubleshooting electricity you can reference the
Suburban water heater manual, page 9 for a schematic.
From previous posts about the same problem, the following failures have been found;
- bad switch on the water heater
- bad heating element (with at least one wire removed, it should read some small resistance across the element screws, not infinity)
- thermostat/hi limit cutout tripped
- bad thermostat/hi limit cutout
- loose wiring on the hot side
- loose wiring on the neutral side
Just make sure you are very careful of the shock hazard when troubleshooting with power on.