Heater issue that i cannot resolve. If you sit and idle the car in cold temperatures outside it will not produce any heat in the car. If you drive it on the highway for a while at 100km plus heat will start to come.

At first the thermostat went so I replaced that and it is functioning as it should. It stays at the recommended level on the guage in the dash (before it was not getting to the recommended "line").

I also got a coolant flush done thinking the coolant might be old or heater core plugged. That did not solve anything.

I also changed the cabin filter and air filter.

Any ideas where to look next. I asked at the dealer (as i got the flush done there as they have some kind of vacuum machine to make sure the coolant gets all sucked out) and the guy said the heater cores never go in these cars. The have only every replaced some in the older XC90s.

The blower fan appears to work you can adjust it high and low.

Is there a door in the coolant system not letting hot into the heater core that is malfunctioning? or some other sensor? or pehrops the climate control system needs a reset or is busted somewhere?

Appreciate any insight. Also note i've got around 150k on this one.