heating problems on 2005 Mercedes-Benz E320

when I turn the heater in my car it only blows cold air

Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
2 answers
It may sound crazy but what how are you turning the heater on? You'll have to press the AC Off button.
Here are some possible answers: http://repairpal.com/i-have-no-heat-what-could-be-wrong