2000 Mercedes Benz 300td AAC blowign hot air, while Center

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This can usually be attributed to one of two problems. First a broken vacuum line for the ac unit is very likely with this complaint. Open your hood and inspect the vacuum lines on and around the firewall. If all appears okay then the next possibilty would be the AC pushbutton control unit which has been known to cause this complaint as well. A broken vacuum line is more than likely the issue and this can be fixed very easily however if no problem is found with the vacuum lines, then the control unit will have to be diagnosed by a MB shop.