RDspaguy
In The Industry
Just turn the temp down so that the actual temp is higher than the set temp. This should turn off the heater. If you still have voltage going to the heater at that point, it is a stuck relay. Remove the board and bring to an electronics shop, where it will take maybe 15 minutes to put in a new relay, and they can determine which it is. At a local shop it should be around $100. You can send it off somewhere, but it will cost more, plus shipping, and you can't bring it back if it didn't work.
I guess that depends on your definition of "easy".It's sounding like a bad relay is a BAD thing, not an easy fix.