Air conditioner on 1998 Mercedes-Benz ML320

When I turn on the air conditioner switch. A clicking sound come from the vents and extremly hot air blows from the vents. This occurs when the A/C is on. What could be the problem.

Asked by for the 1998 Mercedes-Benz ML320
You have a faulty air blend door actuator. Google "detane" and "ML320" and you'll find a good video on how to replace it. It helps to have small hands to repair it this way. Otherwise you have to remove the entire dashboard.
6 answers 2 comments
Your Automatic Climate Control is malfunctioning and needs to be scanned with a good MB capable scanner at a good MB independent shop. The Hot Air is usually a fail safe mode when the Auto Climate Control acts up. It is so people don't freeze in winter, but it is very uncomfortable in Summer.
I am having the same problem in Chicago. The sound is un-nerving! Please let me in on the solution.
blend motor is bad,,,,its a $95 part,,,just whole dash needs to come out to install
So is this going to a be a recall also it drive me nuts!
I am having the same problem. Did you ever figure out what was causing the clicking noise. Mine still works great/blows cold just makes that noise if the switch is on high or in the blue/really cold a/c setting.
Since mine is a '98 during summer I use a copper tube and bypass the heater core. Also I cover core inlets.This allows the a/c to cool and not share heat from the core. I also ture the temp setting to silence the ticking.
I had the same problem. The climate control switch had to be replaced and a few other things. It ran me around $1,700 for parts and labor at a local dealership, not what I intended to pay.