I have experienced this just recently. My wife drives a 1999 ML430 and informed me that the air conditioning was not working. It would not turn on or activate. I found a fuse blown. Cannot remember what it said it went to, but it was a 30A fuse. Anyhow, I replaced it and still the AC did not work. Due to time I put off troubleshooting til later date. The next day my wife said she heard a ticking noise coming from behind the dash. When I turned the temp comtrol to warm the ticking stopped and when I turned it to cool, it started again. This is when I found out it could be the blend air motor that could be causing it from a mechanic friend of mine.

My question is....will this damage/faulty blend air actuator moter being bad cause the AC not to work. Or do I have 2 or more problems at the same time The fan blows, but I do not hear the compressor kick on and the air stays the same temperature feeling.