For max heat you'll want the recirc on to keep reheating cabin air. Otherwise the truck is trying to heat cold outside air.

The IHKA is the climate control unit on the dash. BMW name for it is IHKA.

Not sure where the fresh air door/flap is, I'll see if I can find it on a diagram.

Thermostat sounds plausible as andrew said.

While using recirculation in connection with heating will increase the cabin temp, this can result in fogging of the windows due to trapped moisture.

The heater is normally capable of heating outside air to a comfortable temp as it enters the cabin - in this case it sounds like it cannot. Blocked heater core? :dunno:

Hidden Temp on cluster is test 7 (7a I think)

And I think the 6 cyl should read closer to 96-98 degrees celsius. At least mine do (2 X5's 2 E39', & 1 E46)

As the cabin temp when tested was warmer than the outside ambient temp, setting this IHKA to auto and lowering the temp caused the blower to increase and inversely, increasing the temp above outside ambient temp caused the blower to decrease. I did one temp increment at a time and waited for the blower to adjust (which was rather quick).

No fault codes.

Since this winter, fall temperatures down to a few degrees below freezing. I monitored the coolant temps in real time using INPA and the temp is within specs.

I had to turn that option off due to excessive moisture. Coupled with the lack of heat, the front windows never defog. Yesterday I pulled this IHKA unit to inspect the small fan on the backside. While it was absolutely quiet as it spun around its axis, there is a slight wobble to it. Maybe a deflection of about a mm. There is dust build up but nothing crazy. Preemptively, I sprayed the unit out with condensed air and I am heading to the mountains tonight and will try again with heat at the front.

If you need to use recirc heat to get cabin warm your heater is broken. I’ve driven at -10F=-23.333 c with no problem maintaining 73f=23c also you will cause horrible fogging problems in winter. Recirc is only meant for bursts similar to a jet will used afterburner.

Can you read the status of the heater valves and heater cores?

It has a feeling of a stuck control vane, so find out if the heater cores are brought to a proper temp

I use recirc continuously - but only when I use A/C - no point in cooling outside air all the time. Recirc can be used to reduce humidity, even win winter but you need the A/C on to do this.

+1 on the heater core check - a blocked heater core would behave like this....

My family likes it considerably warmer than that in the winter. More like 85f. :D

And yes, can confirm, does cause fogging. We just blast the defogger for 10 seconds and that clears it all up.

Of course this would not work when temp is below +3 C and AC won't engage.

Okay okay...progress. I put the IHKA back in the dash. Now the passenger side is is toasty and matches the rear output however the driver side vents are still luke warm! Haha! This is consistent with the window, center and floor vents on the driver side.

Soo you need to figure out if the heater core driver side is getting hot then you'll know if the problem is a stuck flapper or a stuck heater valve