Climate control not working

[MrTash]

I know this has nothing to do with what we are talking about on this page but don't know where to post the question but at the moment I've got an issue with my climate control not working it's dead and I've also got the cooling fan running at high speed as soon as I start the engine. This started the other day when I tried to start the car but I had an almost flat battery due to the car standing so long not being used. Charged it up and then all this started been told that the climate control module is the fault as this is what happens when the unit goes down. I've checked all fuses and they are fine but no idea where this module is located or the part number of it other than been told it's under the panel on the passenger side. If I had the part number I'd try an obtain replacement. Everything on the panel is dead no fan or screen demister operation I've been told that this module that controls it is a common fault so anyone got any ideas? My car is a 2011 C220 CDI W204 turbo model.

 

[Blobcat]

I've moved your post to a new thread for you

 

[MrTash]

I've moved your post to a new thread for you

Many thanks.

 

[davemercedes]

I wish I could help - and I'll be extremely interested in the solution - that no doubt, one of our experts will provide or point you towards...

Best of luck with this!

 

[mattkh]

Please describe how you charged the battery in detail.

 

[mioba]

I would be inclined to get the gas levels checked. MB systems are clever. No gas, they shut down to protect the motors as they not getting lubed.

 

[MrTash]

Please describe how you charged the battery in detail.

Hi, yes well I went out to start the car and it turned over until it went flat. I put my charger on the jump and earth posts rather than the battery itself as I've done in the past without issue. Then the car started as normal and I then drove to the car to go and see my son-in-law and noticed the climate controls were off and nothing was working. When I got to him the rad fan was running at high speed. I got back home and started checking everything like the fuses thinking one had blown but all was fine. I mentioned all this to my neighbour who had mercs in the past and he told me there is a climate control module under the passenger side that when it fails this is what happens the system goes dead and the cooling fan kicks in and it's a common issue with Mercs don't know if that's just on the C Class or all models. But up until I tried turning over the car and charging it everything was fine. I'm not getting any fault codes from my OBD tester nor is there any warning lights on the dash just all controls on the climate unit are dead even the screen demisters front and rear. So I'm at a complete loss as to what's wrong at this point but I'm now waiting on an auto electrician getting back to me to get the car booked in to be checked over to see if he can find the problem. I posted this just to see if anyone else has ever had the same issues as me with this type of fault. I must say I can't believe just turning over the car and charging the battery would have caused this fault but then it is a Merc so what would you expect.?

 

[MrTash]

I would be inclined to get the gas levels checked. MB systems are clever. No gas, they shut down to protect the motors as they not getting lubed.

I'd be very surprised if it were that as up until this point everything was working fine including the A/C but I'm having it checked out. But I've been told that the climate control module is a common issue and gives these effects when it packs up but I'll see what the auto electrician can find if anything. I'd point out I'm not getting any error code on OBD nor engine warning lights and if the gas was low I would have thought you get error messages indicating such?

 

[V6Matty]

What reader are you using to read codes, most won’t touch anything on Mercedes other than engine/gearbox faults but even then can be misleading.
At a guess you’ve likely fried the front SAM when connecting the car, might be lucky that it’s just the climate control module but I’m not so sure.
Best coarse of actions here would be to get it on STAR to have modules interrogated individually and tests performed to find the root cause

 

[joderest]

have you tried disconnecting the battery, leaving 30 mins and reconnecting ?
Just a thought

 

[mioba]

Just a thought. some AC units have their own menu for diags. I know thats the case on my W220 atleast. Not sure about your model without Googling. but give it a try.

 

[mattkh]

Hi, yes well I went out to start the car and it turned over until it went flat. I put my charger on the jump and earth posts rather than the battery itself as I've done in the past without issue.

Thanks for the detail. Does your charger have a LOW and a HIGH charging switch.? If so, did you use the HIGH setting?
You may have done the charging as before, but the different thing this time would have been the extremely lack of juice left in the battery, after all the starting you say you did.

 

[MrTash]

Thanks for the detail. Does your charger have a LOW and a HIGH charging switch.? If so, did you use the HIGH setting?
You may have done the charging as before, but the different thing this time would have been the extremely lack of juice left in the battery, after all the starting you say you did.

No, it's a small automatic charger that tells you when it's fully charged. It's a low rated charger and doesn't overcharge. The battery now is at full charge and the car starts fine but still have the same issues with the climate control not working as well as none of the fan settings etc. The only thing that comes on and goes off as normal is the airbag test on the display and when I start the car the cooling fan comes on at high speed. Other than that everything else with the car is working fine but I'm having it checked out by auto electrician in the next few days so I'm hoping he finds what's wrong and what needs doing but I can see this is going to cost a mint just from starting the car or charging the battery complete nuts. I can see me getting rid of this car at the end of this and going for a more reliable make of car other than German.

 

[mattkh]

....... even the screen demisters front and rear.

Do you mean the rear windscreen wired heater? Do you have a switch to turn that ON or OFF? If so, then that would be my next line of investigation.

 

[MrTash]

Do you mean the rear windscreen wired heater? Do you have a switch to turn that ON or OFF? If so, then that would be my next line of investigation.

No, it's both front and rear heaters it's everything on the climate control face no fans, no display lights the lot is dead so nothing at all. In other words, no matter what button you press nothing is working and in turn the rad cooling fan kicks in when you start the engine and runs at very high-speed sound like a jet engine. The two must be related as before any of this happened everything was fine. Like I said in my post I've been told that it's common for the climate control module to go down that gives all these effects but other than being told it's located under the passenger side I have no idea what I'd be looking for unless I've got the part number. But just trying to start the car or putting the battery on charge would cause this to go down just seems nuts to me as I thought that's why you have a 7.5 AMP fuse to protect it with and that should have blown before it had the chance to do anything to the main part. I tell you I've just about had it with all this German rubbish now looking at getting a much better make of car.

 

[mattkh]

Thanks for the detailed explanation. Try a new FUSE no 12, even if the old one looks ok.

 

[MrTash]

I wish I could help - and I'll be extremely interested in the solution - that no doubt, one of our experts will provide or point you towards...

Best of luck with this!

Well, the solution as I was informed by Mercedes Mechanic (independent) is a complete Climate Control unit replacement but at a cost of £484.20 for a brand new one, I've opted and obtained a second hand one for £70 from eBay part Number A 204 900 38 03.

I almost fell off my chair when Mercedes told me the price of a new one talk about being ripped off. So my problem now solved at a more acceptable price I'd say.

 

[davemercedes]

Hey, thanks for the update.
Very well done! Full marks for perseverance and more for finding a pre-owned solution. And come the spring you’ll be good and comfortable!

Was it difficult to fit or did your Mercedes Mechanic do the job?

 

[MrTash]

Hey, thanks for the update.
Very well done! Full marks for perseverance and more for finding a pre-owned solution. And come the spring you’ll be good and comfortable!

Was it difficult to fit or did your Mercedes Mechanic do the job?

No was easy to fit but you need the clip pulling tool where they are located behind the top vent slots and once you have removed this trim it's just a case of then removing the unit from the console. I did it myself in the end rather than them I've provided a Youtube clip that shows how to go about removing the control unit. This is the link

 

[davemercedes]

Aaah - well, once again, full marks for your perseverance.. and looking forward, in 3 months time you'll feel pleasantly comfortable while some are hot and flustered! I'm very lucky that the manager at my local garage (who does all my normal servicing) is something of an AC guru and he checks my system out each time it's serviced. Thankfully, the biggest bill I've had over 6-7 years has been topping up the gas, just one time.