Joe_Villar

My CLK 55 Cabriolet A/C works but there's very little air that comes out of the vents. Even at high fan the air coming out is minor so it doesn't cool off the cabin in Florida weather. The fan is loud like its putting out a lot of air but doesn't correspond to the output from the vents.
Does anyone know or have the same problem? Also if there's a thread that referes to this please send me the link.
Thanks,
Joe V
South Florda

Mercnotworking

Have you tried replacing the cabin air filter?

Mine hadn't been replaced for over 10 years and it made all the difference.

There are quite a lot of YouTube Videos about this.


Good Luck

David

Serndipity

[QUOTE=Joe_Villar;7800153]My CLK 55 Cabriolet A/C works but there's very little air that comes out of the vents. Even at high fan the air coming out is minor so it doesn't cool off the cabin in Florida weather. The fan is loud like its putting out a lot of air but doesn't correspond to the output from the vents. Does anyone know or have the same problem? Also if there's a thread that refers to this please send me the link[ /QUOTE]

Joe.........the HVAC is very complex and I seriously doubt you'll get a definitive thread/link solution.

Mercnotworking has already provided an exemplary suggestion that could explain why your vents are not providing the required air conditioning.

However, if you find that is not the issue, the good news is that, our W208/A208 HVAC push button control module (N22) has sufficient built in diagnostic/test capabilities, upon which even a shade-tree do-it-yourself could diagnose, troubleshoot and repair the system.

Specifically , there are 3 test ( e.g. for actual system values, present diagnostic trouble codes, as well as a flap test).

Our W208/A208's are not Spring chickens and most faults and the procedures/ interpretations of these test are all well known (READ: search is your friend).

Joe_Villar

Thank you for the responses.
I did replace the A/C cabin filter and it was pretty bad. Unfortunately it did not solve the no vent issue. I even tried the A/C without the filter to see if it improved the air flow. No luck either.
I will however try the fault tests. I was able to find a thread that had all the instructions on how to get the codes.
I'm assuming there are flaps somewhere that are not opening causing the loud noise but no vent comes out.
Thank you all for the input
Joe

shaunmlavery

A quick one if you are having issues out of your face vents and you have been messing around under the hood, vacuum lines. Remove your air intake and take a look at your vacuum lines at the rear of the intake. Going off of memory there is a Y and if one of those comes un-done, it will knock out your vents.

As others have said, the A/C system has been touched on a lot. I'm in Texas with my CLK55 and mine is black/black. Basically, it is hot as hell when I get it out and mine is working and I just charged it before the summer! I feel your pain.

Serndipity

I've included the above AC system values test even though you indicated that it works, except for lack of dashboard vent air flow. However, it's a very valuable tool to diagnose and repair various system components. As example, if in step 7, if your refrigerant pressure is low, you won't have icy cold and/or the compressor won't operate, but for about $25 you can purchase a can of R134A with pressure gauge to add refrigerant, which is an easy 5-10 minute DIY.




In the above, you will be able to see any system DTCs. Note that if a DTC is stored, in order for the system to operate properly, the DTC must be cleared (i.e. erased).




Some notes on the above flap test. Long vs short stroke refer to the being open or closed. This test helps to identity and repair a specific malfunctioning vent actuator, in which case there is some additional information needed (e.g. test/remedy section 32 that is not included), because you indicated that the air flow in all of your vents is weak or not existent.

If were me, the first thing I would suspect is a lack of system vacuum, which is required for vent actuator operation. As shown in the below diagram, the system vacuum (i.e. pressures) is supplied by the vehicle's air pump (located in the trunk passenger side), engine vacuum as well as stored in a reservoir (located in the front drivers side wheel well) and then distributed by a switchover value. I would begin by checking the vacuum system for leaks.



Added diagram for the cabin's vacuum line separation point.

Joe_Villar

Fantastic!
Now that is a complete diag setup there. Thank you for the valuable info.

Joe_Villar

I did change the MAP or MAF (one of the two) sensor a few weeks ago and also the air filter. I will look to see if I can find these hoses you mentioned. If I'm not mistaken they should be right in the center close to the firewall.
Joe

Serndipity

As usual, excellent feedback....odds are that you'll have your A/C 100% functional before long.

Specifically, you may have inadvertently mucked up a line that supplies vacuum, though the firewall, to the Y11 Flap switchover valve, which is located inside the dash, behind the glove box.

Here are some links for more information.

https://www.benzworld.org/forums/c20...cuum-hose.html

https://www.benzworld.org/forums/w21...line-help.html

https://www.benzworld.org/forums/w21...cuum-hose.html

https://mbworld.org/forums/clk-class-w208/714194-where-vacuum-distribution-box.html

The bad news is that plastic components frequently disintegrate and break with age, the good news is that , if required, new replacement parts are readily available for very little dollars.


BTW, on our cabriolets (208.465), as noted in step 1 in the values test, whenever the roof is lowered, the N22 soft top controller overrides the B 10/4 in car temperature sensor. Ive found it advantageous to operate my air conditioner manually, instead of automatically. This way with the windows up, the wind screen in place and the A/C manually controlled as needed (e.g. on/off, temperature and fan speed), you can still enjoy driving a convertible, even on the hottest of Summer days.