Its 10 below and we have no heat in our cab. The engine is at operating temp. But only one heater hose is hot. Is there a valve or something electronic that would keep it from actuating to prevent coolant flow through the heater core?
Is your coolant level low of so I just had to replace the turbo coolant feed line from the egr to the turbo causing a coolant leak which would cause no heat in the cab if reservoir was low
I had a similar problem a couple of weeks ago. Much warmer temperatures though in California. My problem turned out to be the EGR valve was causing me to lose coolant.