I have a 2000 Mercedes ML320 that is making a very loud sound from the air conditioning, like something is clogged and it is laboring to push the air out. It is still cooling, but not as well as before it started doing this.It alsodoes it without AC (regular fan and/or heater mode). Does anyone know if this can be fixed without taking it to the dealer? My husband was an ASE certified technician (Jeep) for 20 years, and says that you had to remove the entire dash assembly to repair this problem in the Jeeps. Any help would be greatly appreciated.