2007 Mercedes Benz ML350 My heater is working intermidiatel

Hi mary_1976, Welcome to 2carpros and TY for the donation and selecting us as your auto repair site. Feel free to ask questions at anytime-Merry Christmas and a Happy New Year 2010

Does the heat comes and goes or the blower works when it feels like-give me more description/details to the problem

When I press the on button or the auto or defrost, the lights comes on but no air is coming out. it is compeletly quite and it be like that for like a week and then one day i will turn the key circle on and the heat will work as normal, very powerfully. Then after 2 weeks or so i will turn the car on and wait for it to warm up and turn the heat on and it will not blow. This is in all AC and heater. This problems started when i took the car to the dealer and they changed a cram sharft when I got my car back it never worked. I notified them and they denied it.

Could be a loose connection on the AC/Heater blower circuitry or a problem with the AAC push button control module or the blower motor regulator. You got one sophisticated AC/Heater system, you need to bring it back in and have it check out-

If it possibly be a AC/Heater module can diconnecting the battery reset the module.

Disconnecting the battery is a bad idea -could mess up other parameters, my last suggestion here is bring it in