2021 DMAX - cold temp issues?

[ArrowsmithPML]

Exactly, anything below -30 and all sorts of weird stuff can and will happen. Take for example by simple circuit overhead beacon on the existing truck; in -45 it wasn't working, now in -15 it is working as normal. Goodness knows if you add a computer to the mix what would happen.

[ArrowsmithPML]

1 hour ago, CRApex said:

So my 2020 3500 in is right now for a DEF tank heater issue.  11,000 miles.  The heater is part of the tank assy so the tank needs to be replaced.  The dealer told me it was on back order and could be a month before they see it.  Truck is undriveable due to looming limp mode speed reduction so it sits at the dealer.  Otherwise it starts fine in the cold.

That isn't something I want to hear.