Electric water heater (no hot water)
Power enters a typical water heater through a high temperature limit thermostat. It's almost always the topmost of anything. It's also the only one that breaks both legs. Possibly one half of this thermostat is bad. A lot of them have a red reset button, they press sort of hard. Since your fingers are close to the terminals, press the button while the power is off.
If the tank is completely cold, the top element will come on first. I'm showing my age here, but many years ago this feature was called 'quick recovery'. It would heat up only the top part of the water in the tank, and indeed much quicker than heating the whole tank.
When the top element thermostat is up to temperature, it transfers power to the bottom element. If it's cold down there, the bottom element heats the rest of the tank. Then its thermostat turns it off.
As stated earlier, the high temperature limit is two pole. It kills all power to both elements. The operating thermostats (top and bottom) are one pole. They only break one leg, not both. A lot of these are combination units with the high limit and the top operating thermostat all-in-one.
The top operating thermostat is double throw, it directs power to either the top element or the bottom. The bottom thermostat is single pole. It's either on or off.
Check to see if you have 240 at the top of the high limit. If no, you'll need to look between the heater and the panel. Look first at the little box where the power cable enters the heater. A very common spot for burnt up wires.
If you have 240 at the top of the high limit, check the bottom of it. If it's 240 also, check across the top operating thermostat. Check first from the common (it might be a sort of link from the high limit to the operating thermostat) to the wire that goes to the top element. If 240, the thermostat is bad.
17 ohms is about right for a 3500 watt element, but check for voltage across the element anyway. Most likely, the problem will be in the top part of the heater.