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When I insert the key before starting the car or after remove the key after turning the car off, there is a quick and constant ticking / clicking noise that goes on for some time, for a minute or two. The sound comes from somewhere behind the instrument cluster and its trim. The sound is Similar to a relay that closes and opens quickly many times. I attached a video of it happening.
the first two days the sound was not loud but you can easily hear it. Now the volume is lower, it’s harder to hear it but you can still hear it well.
has this happened to anyone before? What could be the issue?
Read below and use your ear close up to hear the Y58/1 fuel vapor purge valve which if on my car is close to LEFT headlight. It does sound familiar to my ear. https://mbworld.org/forums/e-class-w...rge-valve.html
I must admit The sound is identical, but it’s not coming from the area you mentioned. I also could not hear the noise coming from the fuse box, thinking it was maybe a bad relay . Maybe there is a motor in the dash? For the air flaps in the vents ? I’ll have to take the trims out when I get the opportunity, these days it’s freezing cold outside.
I disconnected the battery and after reconnecting it, I never heard the ticking noise again, it stopped.
Recently I noticed that the AC blows warm/hot air, regardless of what temperature I set. In some thread from a different forum someone said that the problem is related to the AC flap motor, when it breaks, it’s not separating the cold air from the warm air, and thus it always blows warm air. And guess what, when that part fails, it makes that exact ticking noise I was talking about.
The part would be no. 190 ( a22 182 000 42 or a22 190 669 00 ) from this picture I found online. Could someone help me with some disassembly instructions to get to that part?
Ben, your careful detective works pays off with a quick free repair.
The HVAC flap actuators are built to deliver the chaos you have just met:
crazy temperatures instead of climate comfort.
The crazy flap struggle is made specially troublesome with the heater core having NO flow control by design. 🤪
Heater is always on full 200°F heat regardless of AC 50°F request - When the blend door isn't shut, the poor AC cooling gets your motivated for an extended milking-rodeo at the service desk 😊
My simple work around is to partially pinch your heater hose once winter's over. ✌️
one of many HVAC actuators
There are half a dozen identical actuators located on the outside of the HVAC box. I recall each module being fastened by 3x screws most of them uneasy to get to under the dashboard.
Armchair review: unsoldered circuit board pins... power surges
8x poor connections... motor uses twin coils
DRY gear reduction.... short lived performance
AFTER: soldered and lubricated assembly... normal service life
If you replace these units new, the same built-in issue will still be there. So it's better to fix the problem right the first time.
access made easy
I do not have the mapping of what actuator works what flap function... I simply fixed them all as I was fixing my clunky steering column which I really recommend doing if your up for it. > Bonus: guess what's inside your master flap controller.......
Last edited by CaliBenzDriver; Jan 12, 2023 at 04:32 PM.
I envy your fingers and hand dexterity Cali
I hate INTERIOR work !!! Out of 10, I break something like 2-3 times when dealing with those friction fit clip/hook/insert and what not.
How many of these step motor/flap are actually in use ?
Parts list shown item 190 Stepper Motor as 5 units..wow
This ebay seller unit has 2 stepper motors visible, which I believe one ( top one ) is for upward air to windshield or DEFROST. https://www.ebay.com/itm/295209005948
Cali, when you access yours, its the lower one, right ?
Can you hand access the top one ?
Last edited by S-Prihadi; Jan 13, 2023 at 03:11 AM.
Surya you know there is a collection of identical actuators to switch the HVAC flaps as desired. We can easily guess the function on some of them... the hardest working flap is the blending door helping to control temperature
top side and front flap actuators
passenger Fresh air/Recycle flap actuator
there are 2 more actuators located under the box above the floor carpet... likely blending doors + feet selectors?
Bonus for enhanced cooling:
As always when we put our thinking cap on, we get to understand more than what we bargained for...
Both In/Out heater pipes are uninsulated and help toat the occupants, the center speaker dual-coils, the Display module and the Comand head unit with it's cuite dedicated cool8ng blower while the 200°F pipes are steaming near by.
Imagine the thermal shock on the windshield when the car is shutoff and heat overcomes the cold AC: does that help crack the windshield across? uninsulated heater pipes... seriously?
A little sprayed insulation would help contain unwanted heat to make weak AC a knotch closer to normal. TXV access location
I don't know if it can come out in engine bay or complete HVAC need to come out??
Last edited by CaliBenzDriver; Jan 14, 2023 at 02:07 PM.
I envy your fingers and hand dexterity Cali
I hate INTERIOR work !!! Out of 10, I break something like 2-3 times when dealing with those friction fit clip/hook/insert and what not.
Master Surya, every good thing that has happened to my car, I can in part attribute it to you!
As a token of my appreciation I can offer to solder these actuator PCB's for free as a thank you
I know how hot Singapore weather is year round, I can imagine the vital importance of good AC in Jakarta. So through in your solderless HVAC module as well for good measure
What your fat fingers can't do, you more than make up for it in the test & troubleshooting dept.
We fix things slightly differently with our own bias but we agree that basic performance & reliability are non-negociable. MB are not so difficult to fix once we learn to deal with the standard Easter eggs.
In another thread, wiseman Juan @juanmor40 noted that his pressures and compressor tested fine but his AC cooling was still poor...
Let's fix the AC :
- insulate heater pipes over the HVAC box
- pinch coolant hose in engine bay
- rework flakey flap actuators
- rework unsoldered HVAC Module !
(- wrap Hi/Lo pressure lines ✌️)
Terima kasih!
Last edited by CaliBenzDriver; Jan 16, 2023 at 05:44 PM.
I did play with HVAC the actuators angle using Autel , for fun and when I activated the extra airflow mode, the one for the foot well..... but never in my mind to imagine the claustrophobic nightmare components which lies behind the dashboard. No no no, me too scared
Only after Deni posted item 190, and due to that, I was imagining the prospect if I were to need to access those flaps/stepper motor.... how many small parts I would break ... LOL.
Back to Deni's possible ticking sound from item 190.
I recalled using Autel or Xentry, we can get actuation angle value target vs actual....if I recall correctly there are 2 values.
And then your photo of the internal mechanism of #190.
I think Deni's #190 is trying to reach target angle , but due to some problem it could not reach the target angle and hence the ticking sound is probably the motor and gear
keep running but jumping from possibly a missing teeth or spline...something like that.
Or maybe #190's range/angle sensor defective ?
I believe at some point the module controlling this #190 motor may stop when it has tried too long, as safety measure.... maybe.
Engine OFF and then ON again may cycle the ticking sound again, if indeed such safety measure is employed by MB.
Using a scanner I am sure the actual achieved angle vs target angle of the suspect #190 can be read so Deni can target directly the suspected #190 unit.
This kind of fault wont likely be engine check light material, but scanner can read it.
Like how my alternator LIN disconnected is not important enough for engine check light material, as MB knows the alternator own regulator will be handling the charging profile.
The actuator has no mechanical device to track where the flap position is located.
The module initialisation is done dynamically such as once the flap is recognized as being at the reset position the matching Minimum value is set.
From that extreme position there are x-many intermediate steps available to track position all the way to the other extreme position being opened.
The fancy DC-Brushless motor uses two coils *not* for in/out but likely to help track position. One coil drives the shaft while the other counts poles switchings.
Whatever way is used to incrementally position the flap with minimal reference (high current or lack of steps), we can see it is important for the shaft not skip steps. When that happens the controller looses the flap position until a self-reset is performed. That's what the tic-tic sound is all about.
> Solderless delivery scheme:
Solderless board connection introduce high DC power drop voltage. The IC chip is getting super dirty power with surges spikes caused by the motor feeding through resistive pins.
Now imagine the control chip trying to count current steps with a dirty power supply. At some point it becomes impossible!
To make sure all goes according to plans the small on-board .1uF caps are unable to smooth power surges like a larger 1000uF could.
When the solderless game come into play controller reset causes further damaging high currents to get more lost... nicely done by Mahle!
✌️
Last edited by CaliBenzDriver; Jan 14, 2023 at 04:27 PM.
It would be wise to first bidirectionally control the suspected flap motor with a scanner and confirm its ID and position.
Hhmmm another fear factor I hate to think about
Internally, the #190 stepper motor the one on W203 is not the same as the W212. Very loud one below.
I watched both W203 video and kept wondering why is the dude disassembling most of the central console to access HVAC actuators...
(Perhaps the W203 HVAC box has actuators located behind our Comand unit? - 90% chance: not there)
On W212 HVAC actuators are accessed by removing dashboard lower plastic covers.
I think this is very straight forward (remember to go carefully so you do not to yank the temp sensor$$$) - Both of these plastic pans are out under 10mn. If you still think dismantling the central console is faster then at least you'll get to glance at some EXTRA REPAIR OPPORTUNITIES:
EIS keyslot < must !✌️!
Steering column < must !✌️!
HVAC module
HVAC Actuators
LCP,
Console Rotary dial module,
Tranny "E/S button" module,
😎
Do it right once OR else more often:
Video shows how to discover which of the actuators does the tic-toc reset clicks by LISTENING ... love simplicity 😊
Once you know exactly where all the racket is coming from, you can either fix or replace that one module or FIX ALL OF THEM FOR FREE 😁
Personally I elected to address all known HVAC actuators at once. Don't be afraid to remove your column as time permit...
>> INSULATING OUR 200°F PIPES >>: easy to insulate ?!?
LOW EXPANSION insulation spray foam
beware crack-foam is a bit too invasive...
So today I was looking for a spray can of Flex-Seal when I came across the light spray foam.
I think that of "PLASTI-DIP" spray is going to help me insulate my exposed heater core pipes.
Bikers use PLASTI-DIP to paint motorcycle exhaust shields... so 200F no problem!
Couple coats with dry time in between I am sure will work wonder to boost AC efficiency.
Good cars use insulated HVAC pipes , Taxis cabs and the likes.
Germans engineering enhanced by Toyota is the best, not the greatest.
Last edited by CaliBenzDriver; Jan 15, 2023 at 06:25 AM.
Wow, thank you all for Your input. Very valuable information!
right Now since it’s winter it is not such a big problem. I don’t know what I’ll do when it gets warmer though, this job seems to be way beyond my abilities, it’s more than I expected.
I highly appreciate your help
Dumb question, but which one would be the heater hose you mentioned, that could be pinched to partially resolve the issue?
After some more analytical thinking, I’m guessing maybe the fault is not the blend air flaps... the reasoning is this. That previous ticking noise was heard only behind the dash, behind the steering wheel. On the passenger side it was not noticeable. If only one flap actuator was broken, then in theory I should get that hot air only in that vent / area, right?
but I’m getting hot warm Air through all the vents in the car. Driver passenger side even in the rear vents, the air is warm / hot.
So then, is there maybe like a main flap?
Or maybe it’s just something else that’s the problem, something much simpler.. in some thread for a different model ( https://mbworld.org/forums/s-class-w221/819261-heater-not-working-anywhere.html ) the problem seemed to be the “heater control valve”, though the problem is the other way around: be heat was coming though the vents. Will have to dig deeper in regards to this.
just sharing my thoughts
There is no heater valve for W212 with M276. Its a free flow of hot coolant to heater core at all times.
M278 I know has heater valve electrically operated, but the newer replacement P/N has no more heater valve, again open pipe only.
Diesel engines I don't know.
You need a decent scanner or Xentry which can test/run those flaps. That is the only non intrusive way to test.
Attached is W212 Service Manual, go to PDF page 119. It has all the flaps information but make sure you know ur HVAC is a 580 or a 581 code. Mine is a 580 as per Data Card.
However I think the information is not so correct. I have LEFT and RIGHT footwell airflow, meaning there is a flap but those 2 flaps are marked 581.
I have defroster flap too for windshield, but its stated as code 518
=======ADD===============
Found old scanner photo for the HVAC flaps on my 580 hvac code. I got 5 flaps only
I believe the M2/6 and the M2/7 are the HOT or COLD blend flaps.
There are 2 blend flaps, yes, option 580 can do split setting for HVAC, as though as car divided between driver and front passenger
To test the FLAP
Last edited by S-Prihadi; Jan 25, 2023 at 11:58 AM.
Reason: ADD INFO
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when dealing with those friction fit clip/hook/insert and what not.
No no no, me too scared
