That is what I am wondering. It looks like the heater has been used in a lot of different applications, so I expected there to be some parts stock.
BTW, great diagnostic work! I love reading threads that begin with a newly-reported (?) problem, contain diagnosis in real time with the thread, and end, hopefully, with a happy resolution.
Thank you! I don't spend a lot of time posting on forums, mostly because the diagnostic/ repair has already been covered in another post somewhere. I searched everywhere for this problem without a definitive answer, and considering it could have burned a car down, it is a good issue to cover.
As for the design
this is what my heater looks like.
This appears to be an upgraded version, which looks far more robust. Based on my failure, my thought is the factory over torqued the nut for electrical connector which caused a weak spot where the stud sits in the housing. Enough time, vibration and some cold Edmonton weather would be enough to degrade the over torqued connection. I don't believe that there is any issue with the control circuit, as all of the wiring was in great shape.
I will update again once I hear back from the dealer on the back order status.