What you are facing is a sticking regulator valve in the compressor, its the piece that you see going in sideways into the compressor on its tailpiece.

The usual reason for stalling is clogged up system or wrong servicing procedure. e.g. lots of ac shops when they replace this compressor dont fill the crankcase of the compressor with oil just like its required on chevy harrison V5 compressors.

The GM cars with those face the same problem too - specially on low refrigerant charge also - the valve sticks on one end too long and takes a while to get back to work.

All the above is only correct if your HVAC manifold set proves that the system is throttling down - if the system is stable and you get warm air, the heater control valves are being activated - this is a climate control problem, the sensor for cabin temperature is right next to the dome lamp - its the little grille you see there, get a duster can to blow it out - it may have accumulated lint or dirt there.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)