I recently noticed I only get heat in the front. My rear zone will not produce heat. I've gone through the various control options like mono and controlling it in the rear. Only cold air blows out the back regardless of the temperature setting.

Any ideas on how to fix this?

 

it aint that simple of a system------go to MB WIS for the 25 documents on diagnosing your AC and heating system by the VIN

 

I don't have access to MB WIS. Was hoping to find someone that's had this problem before and had a solution.

 

Off the top of my head I'd guess it is a failure in the air duct control. The system diverts warm air flow to the second row seats.

To be honest, I'd be inclined to get fuzzy slippers and a blanket for your second row passengers.

Fancy pants features often fail early.