My D250 soon puts out warm air, we've regularly had temperatures below freezing recently and after a mile or so l am getting warm air from the heater.

l don't use Auto, l use manual with the blower on 3 and set to footwells only.

When l first start the engine the blower clears the screen and then reverts to the settings l've selected. Initially there's hardly any air flow but it quickly starts producing warm air.

One thing, out of our house is up hill for around 1/2 mile which probably helps!

 

I've been banging on about this for about 2 years now but I finally found proof that a 2020 Defender (110 X like mine) has the aux electric heater installed. Here

In the past 24 hours, I've driven 3 LR's....my very scientific study is as follows:

2020 Defender - takes at least 2.1 miles for the heat to be felt in the car normal city/suburb driving. Does not matter in auto, or manually cranking temp and fan.
1988 Range Rover - warm air 2 blocks down the road
2000 Disco 2 - warm air begins about 1/2 mile down the road

I am 100% convinced that there is a glitch with the computer programming in the 2020 L663. This aux heater is not turning on, if it were, I would get heat! The whole point of the aux heater is to kick the heat in earlier than the engine coolant, I believe.

 

I have had the same thought. Even took it to the dealer and they said it is working as designed. I even saw in the CCf it is selected as installed but it definitely doesn't seem to be working.

 

I’m pretty sure mine was working fine last winter. I tested it and had warm, air come out in a stationary car,

At some point it stopped working. I don’t know why, but in the service manual it states a few prerequisites for it’s operation, maybe something is not ok for it to start.

This winter I’ve been missing it. It’s a short 15km to work and by the time it’s warm I’m there.

 

lt may depend on battery voltage, like the stop/start operation.