Hate for this to be first post, but I have search and read most post concerning heating issues with no luck.

The car has no heat (only blows cold air),
When I switch to defrost the windshield vents start blowing, then switch to dash vents.

Items Checked So Far:
Reset of climate control unit
Diagnostic ran with no faults showing (Trusted Indy Shop)
Replaced climate control unit (Indy Mechanic thought might be place to start with no codes)
A/C is fine, charge has been checked
Replaced thermostat
Checked auxiliary water pump (runs and hoses feel like fluid is flowing)

And still have no heat. Am not opposed to spending the cash to fix, just opposed to getting shafted at a stealership. any help or ideas would be greatly appreciated

 

fuse? or climate control unit is bad?i watched enough top gear to know that troll this a lot by breaking the control

http://www.ebay.com/itm/Mercedes-W203-C230-C240-C320-Temperature-Climate-AC-Heater-Dash-Control-2001-05-/331076637365?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A2002%7CModel%3AC230&hash=item4d15b492b5&vxp=mtr
60 days return, worth a shot

 

Thanks for your reply, But I have already replaced the Climate control unit with a pre-checked unit from my mechanic

 

stepper motors or something like that.. is what i was told in my first post about heat issues..

 

HEATER CONTROL VALVE?

Looks like this.

 

Thanks for the ideas.

Wouldn't a stepper motor throw a code? (if I am wrong let me know) during the flap reset all vents and flaps seem to work properly for me, and though computer for mechanic as well (thus the confusion).

I have been looking for a heater control valve, on the car, but still have not been able to locate one, even when looking at parts diagrams on my mercedes parts as well as other sites.

 

It maybe that the 2002 C230's don't have a Heater Control Valve.

A parts search shows none found for 2002, you can call your dealer parts dept. to verify.

Not sure what else it could be, did you hook it to a STAR and verify all the flaps were opening correctly?

I see a trip to the Dealership in you future.

 

yes the indy dealer ran ran the diagnostics on star and was puzzled. that is why he suggested replacing the climate control unit, because no codes, flas and steppers motors were working. this is driving me crazy.
My little sister gave the car to me as a present, and she had several people look at the heat problem as well, everyone just scratches their head. maybe an very expensive trip to the dealer shortly, closest one to me is 150 miles away (yikes)

 

There are no Duo Valves on a W203.

If the Aux pump is circulating hot water then you likely have a stuck blending flap, dead stepper motor, broken blending flap arm or the controller is toast.

3 is the HVAC evapourator & 4 is the heater matrix.

 

At this point I'd have to check if the Aux Pump was really pumping, seems like it takes the place of the Heater Control Valve.

 

Thanks for the help, going to try the blender flap and do the arm replace while I am there. maybe I'll get lucky

 

I didn't think the AUX pump has to work to get heat. Mine had been dead for three years and my heat worked fine. I did have an issue with my heat on the driver side when the gears got stuck a few years ago but the heat still worked on the passenger side just fine.

 

The Aux pump is only there to provide heat after the car has been shut down. It does improve hot water flow however.

The car's water pump will provide adequate circulation while running.

 

[im not sure how old this post is? Honestly it doesn't matter because I'm throwing in my suggestion anyways. So here it is... since it seems like you pretty much fixed everything then maybe you just need to flush your heater core. Worked for me in my Chevy when my truck wasn't blowing any heat. Just a suggestion I wanted to add incase it can help someone that needs the easy fix reminded to them, after all the costly fixes failed.