hvac system blows hot air to rear seating area with temp control at low

What is your question?

It does this intermittently. Front AC ducts blow cold while the rear blows full hot.

What makes this problem better or worse?

Sometimes if I cycle the digital HVAC temp to full hot and them back to full cold, sometimes this cures the problem but returns to blowing hot air in short order.hot air

How long has your 2011 Mercedes-Benz CLS550 had this problem?

3 months