The heat vents are under the front seats, facing the back. The vents on the back of the seats are A/C vents. Normally, if you have the air distribution set on automatic (which I assume in cold weather would be delivering air to the floor vents), there shouldn't be much air coming from those vents. If you have air delivery mode forced to the
A BMW E60 AC compressor replacement is most likely necessary if your car has over 120,000 miles and is not blowing cold air. The well-known Achilles Heel of the BMW E60/61 5 series climate control system is its air-conditioning refrigerant compressor. It was a freon leak and it would blow cold on passenger side, moderate on the center vent and hot on the driver's side. Even with dual zone, its still one compressor so I'd check freon. It happened on our 2017 40e on RHS as well, but only when the engine was running and got put to normal running temperature.4. Open the valve momentarily on the gauge set or hose to blow all air out of the line (this is necessary to keep from introducing air and moisture into your A/C system). 5. Connect the gauge set or hose to the low side A/C service fitting on the vehicle.