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Replacement parts for Whirlpool RM770PXBQ2 ELECTRIC RANGE AND OVEN | AppliancePartsPros.com

I could not find a wiring diagram for this unit.

18 ohms seems correct . It would work out to a 2700 watt element.

You have continuity and voltage so it should heat up.
The only thing I can think of is that another component (probably the broil control relay's contacts) have a high resistance. So you see the voltage but when the lower resistance element is connected all or most of the voltage is dropped across the contacts and the element gets little or nothing.

The way to check this is to now test with the element connected and see what the 220 does.

Another possibility is that the heating wire in the element has a break and when it heats up a bit this break opens. This has very low odds as usually the element will blow at the break.

[COLOR="DarkRed"]Could it possibly be the thermostat? While I see a thermostat listed on the parts list, it is no where to be found.[/COLOR]
I cannot say if the thermostat is the problem as I cannot find a wiring diagram. Also it it was open you should not see 220 at the elements wires but it may have a high resistance and may be for the broil element.
It may be worth removing power from the unit and checking it with a meter.

[COLOR="DarkRed"] Is it behind the oven box?[/COLOR]
I am not sure but that is a common place for them to be.

[COLOR="DarkRed"]I replaced the oven sensor about a year ago so that should be OK.[/COLOR]
A sensor problem would probably show up as the oven coming ready when in fact it is not.

[COLOR="DarkRed"]Lastly, I remember that over the years we found honeycomb like pieces in the oven. Were these standoffs of some type for the broiler element? Does this have any relevance?[/COLOR]
I do not think so. I think it was from the smoke eliminator. Click on it's picture (Item 9 in Section 7) for a better view of it