2004-C230

I have a problem that is intermittent.

Vehicle: 2004 C230 Kompressor 4dr manual / sport-edition

About four days ago ... it was unusually hot (about 95). The car was parked outside all afternoon. I got in and put the AC ON at full blast. Fan was set to maximum (i.e. not Auto-Climate mode). Both driver and passenger side temp dials were set all the way to the left (64 degree marker).

Noticed a strange thing ... the passenger side vents was blowing really cold air ... while the drivers side was definitely not cold at all (but it was not hot either).

While still driving ... I started fiddling with the settings. Turned off the fan. Turned on Auto-Climate. Did not help. Turned off Auto-Climate. Turned on Manual mode again. Did not help. Then finally, I turned the fan off and then turned it back on *but* at very low speed. After about a few seconds I noticed that gradually the driver side vents began to blow cold air ... and after about five minutes ... they were all behaving consistent.

Yesterday I took the car out and this time I did not start the fan at full blast .. instead I turned it on low (the same trick) and after confirming that all sides were blowing cold air ... I raised the fan speed. That seemed to do the trick.

Has anybody noticed this behavior ?

On a side-note (perhaps related) ... I have noticed that every time I turn the fan on ... I hear a ball-bearing grinding/squealing/hissing sound coming from behind the dash (towards the driver's side). Its not really loud ... but very audible. This happens even if I turn off the A/C by pressing the A/C OFF button (with fan still on). The sound comes on for some seconds and then goes off ... and then comes back again after a couple of minutes. Its almost like there is a fan that goes off/on every few minutes.

Is that related ?

Thanks !!!

LILBENZ230

Could be. I don't know the re-synch procedure for the pre-facelift, but there should be a combination of buttons you can hold down on the climate control where it will run through a test to make sure everything is synched up. Maybe someone can chime in here.

jogger

i had the same symptoms and recharged the a.c. with a DIY kit and it works fine now.

SteveL1

Mine started doing the same thing today. Record high of 107!!! Tried changing controls with no luck but did not turn the fan all the off like the OP did. Will try that in the AM but really curious what causes this? I also get an intermitent hissing sound as if something is turning on and off regardless of fan speed.

SteveL1

Ran a few tests to see if I could reset something so I turned off the fan which turns off the A/C light. Noticed there was still a small amount of air flow coming from the vents whcih I thought was weird. Turn car off, wait a few seconds and turn back on with fan in off position. Turned on fan to #1 and hit A/C button. Immediately noticed cold air coming from both sides now. Took a temp reading with an infared temp gauge and got as low as 42 degrees from center passenger vent and 45* from drivers side. Things are looking up.

Turned fan speed up to #3 and kept checking temp readings. Drivers side was always about 5* warmer than the passenger side. Turned fan up to 6 and after about a minute, noticed temp on drivers side going up and passenger side staying cold. Almost 15-20* difference between the two sides at high speed. Turned fan back down to #1 and nothing changed. Drivers side still warm.

Turned off car, let it sit a while and started over with fan and A/C off. Turn A/C on with fan at low speed and get cold out of both sides again. Even changed vent position to floor outlets and got the 5* difference between sides.

WTF is going on?

2004-C230

SteveL1 ..I am the OP ... did some more reading around this forum and others ... seems to suggest that freon might be low. I plan to take it into a shop to verify but because of other stuff on my plate ... will have to do it late next week. Meanwhile, if you happen to try the Freon fix ... let us know here.

As to why passenger side is colder ... MB probably figured that its better to keep the wives in the passenger-seat happier.

Thanks !!

atmsanchez

yea i had same problem few months ago, added freon and its fine now.

jogger

i read in a post that when it is colder in one side is related to low freon and when the temp difference is front to back it is due to bad actuators

2004-C230

I am the original poster ...

Last week, drove to my local AC shop and was told that the freon levels were low. Had it recharged and tested for $99.00

Result?
- AC is cooling properly and temp is consistent from all vents.
- The ball-bearing grinding squealing kinda sound that I used to hear ... is GONE !

Fix worked. Thanks to all !!

machulsky

hi there.
I have another problem.. my air vents doesn't work..
I switch the air flow to the maximum, but almost nothing comes out..
only on my side, the drivers side, it works and blows on the windshield, but it's anyway not on maximum, if You got what I mean..
and when I start the car, while it's cold, there is like a knocking from the passenger side in the panel.
checked the cabin air filter, it's OK and clear.
so I guess there's a problem with the small engine inside there.. anyone knows how to fix it or to get near it ?
MB C220 Elegance 2001.

sorry for my english if so, and best regards form Latvian Mercedes-Benz owners.

SunnyRayToronto

At the top of this W203 forum are the "sticky",... there is a sticky about stepper motor,... read it,... live it,... love it,...
https://mbworld.org/forums/c-class-w...g-hissing.html

Anyways,... do the HVAC resynch and play with the HVAC control to figure out which vent isn't working,.... likely the foot-well air vent on pre 2003 W-CL203s,... usually $20 plastic part,... you can DIY but it takes a while,...