amanonfire

So my AC is not blowing on my driver's side at all, yet blowing cold on the passenger side out of all vents. I performed the climatronic easter egg, and the lights blinked for like 10 mins and the system kept cycling. This is supposed to indicate that something is wrong, since it shuts off after 30 secs if all is good - right?

I'll assume this is a stepper motor or broken linkage problem. Now which one is it?

LinDenKid

Same problem here

WaveyKat

me too ...well i get air but it doesnt blow as hard as the passenger side.. i think my Stepper Motor Linkage M2/19 is bad!

amanonfire

M2/19 is "fresh air for left side" which I'll assume is driver's side.

I think mine is M2/6 "left blend" which looks like a PITA to get to.

Glyn M Ruck

Sorry to say it's probably stepper motor or arm. I'm not posting diagram because it's obvious you have one. If no clicks then likely SM. Do you have Thermatic or Thermatronic?

LinDenKid

I dont , my ac wasn't working at all , and i recharged it and now it just blows cold air through the passenger side...

Glyn M Ruck

Here is pdf of Thermatronic as fitted to 320 & Thermatic as fitted to c240 in USA - I expect yours is Thermatic i.e. C240 diagram. Both were available in other markets on all models but not USA.

TruTaing

I would like to say: I hate these damn failing stepper motors with a passion. :x Makes me bitter everytime I see someone else w/ the same issues ive got :x

amanonfire

I have a C230 with the manual climate control - call it what you want!

Resetting the climate control (aka climate control easter egg) helped, as I guess it kicked a motor loose, or jiggled a broken stepper arm.

Glyn M Ruck

Then you like me are lucky - We have Thermatic - We only have 6 motors & arms to go wrong & not 10 like the Thermatronic.

amanonfire

Anyone with an idea of the level of difficulty of getting at the blend stepper motors (M2/6 or M2/7)?

The defrost ones are apparently a PITA and require removing the entire dash, the foot well ones are beside the radio behind the dash, I'm guessing these are buried way behind the ignition or glovebox.

Glyn M Ruck

PM mleskovar

mleskovar

The C320 HVAC is more complicated and has less room for repair because of the extra cabin charcoal filters (I keep the filter 'on', great feature). I haven't worked on a 230 or 240 HVAC so I'm guessing but it looks like M2/7 is accessible on the right side of the HVAC unit. I don't know about M2/6 & M2/16.

ELGUERO559

ok so i have the dash out completly replaced all stepper moters that were not working checked all conections made sure all flaps are opening and closing like they should and i still cant get any cold air on driver side only on the passenger side now driver side does blow air just not cold air can any one help im stuck and been looking at this car for about a week

mleskovar

Did you run the stepper motor sync test with the dash off and watch all the flaps open/close and feel the air start/stop at each? And did it run to completion and stop, or just keep cycling? If it never stopped then it sensed a failure. If you look at the HVAC paper posted in this forum you can see how the air is routed throughout the system.

ELGUERO559

yes i did run the sync test it cycled and then stopped after the cycle was complete and i still have the dash out so i can see everything moving but just cant get any cold air out the driver side

mleskovar

That doesn't make sense. If air is coming out of all the vents during the test, and cold/AC air come out on the passenger side, then it should come out on the drivers side. As a guess.....I think your left blend air flap or motor isn't working. Have you found the paper on the forum yet?

ELGUERO559

yea ive printed a ton of papers showing air circulation and all the flaps i even went as far as removing stepper moters and opening and closing each and every vent manualy and still no cold air on driver side so i dont no what is going on thanks for the help

mleskovar

Which vents do not produce cold air? All of them on the driver's side? Do those same vents blast warm or ambient air only? Both sides share the same heating and cooling cores so if all the vents don't work on one side then the only common denominator is M2/6.

ELGUERO559

yes all the vents on the driver side only blast warm air if i switch it to heater both sides blow hot air but when i go back to ac only pass side blows cold and driver side blows cool not cold ive checked the m2/6 even switched it out with other moters and nothing changes

ELGUERO559

ok so i took the ac box with alll the vents apart and when i turned the ac on i found that only one side of the evaperator is getting cold could the be a blockage in the evaperator or did it go bad anyone got any ideas

Glyn M Ruck

If refrigerant charge is correct & high side & low side pressures read correctly you need a new evapourator.

rmueller

I have the same problem 2002 C32AMG, cold air on passenger side, not so cold on Drivers side. Did have other problems with flap arms, but have corrected all that. Also removed air blend actuator and can manually move everything, but still not cold on drivers side. What was the final outcome? Need an evaporator or is there a way to "clear the blockage"? Evac the system, pressurize or draw vacuum (or cycle of both?), then add refrigerant? I'd deal, but daughter is killing me and not prepared to pay 18-22 hour dealer repair I've seen for evap replacement?

peasngrits

Just found out I have the same problem on wife's 02 C230 SC. Warm air on drivers side and cool to cold on passenger side. Cycled through all distribution modes and it was consistent on all vents. Had my pressure checked and it was about 42 psi (side closest to rear of compressor)

lordgpd

This is exactly my problem and figured I need to replace the m2/6 stepper but is that not the case here. How did you resolve the problem?