Cabin heater blows cold air when departure time is set

[EiB]

Hi guys!

2021 Explorer PHEV here. Has anyone ever had the cabin heater blow cold air when using the departure time function and set to a warm cabin? It is -8 degC when this happens with this car. This must be a fault, unless the car prioritizes warming up the battery. The car also draws low power from the charging box and less than the approximately 15 amps it draws at max.

It also blows cold air when using the remote start function in warmer weather ( above approx. 3degC). Above a certain ambient temperature point the car is set to not fire up the engine, and I believe it then relies upon the high voltage battery to varm the cabin coolant via a PTC heater.

Also, when driving in EV mode above ambient temperatures where the engine will not fire up, the cabin heater gradually looses heat and starts blowing cold air after some time. The engine coolant temp gauge also drops all the way to the low side.

Did anyone experience faults like these, and might have an idea what could cause described failures modes?

Thanks!

 

[EiB]

Hi,

An update with more failure modes:

- Cabin pre-heating also fails in temperatures well above 0 degC. The heater doesn't turn on.

-When starting the vehicle and EV mode enabled, the HVAC doesn't heat up the air and instead blows cold air.

Usually one can observe that the coolant liquid temperature gauge reached the area above the cold zone, when the PTC heater has warmed it sufficiently. See attached photo. But this doesn't always happen.