MB CLK 240 2003 intermittent knocking noise from dash board.

[pmeatonmobile]

I have removed the glove box and there is a control unit MB part number A2038201642 which is flicking and causing the annoying knocking. At the same time I removed the heater blower motor to investigate a noise from the blades. This was like a parking ticket clicking but on investigation was found to be a sensor, presumably heater input air temp. This was dangling from its wiring in the heater blower blades. It was dislodged from its mount when the car battery was changed by another garage.
Please can someone experiencing the same problem help me to decide is it the heater control unit or the air input temperature sensor that is causing the strange knocking? Both components are expensive, ideally I would change both.
Please can anyone help?

 

[WG M-B]

It sounds like one of the heater flap motors. You will probably need a star machine to find out which one

 

[pmeatonmobile]

Knocks from dash

It is a flap motor, the one I mentioned earlier. But can the sensor below the pollen filter housing if knocked about by the heater fan cause a problem with this particular flap motor? Thank you for your reply it is great that someone is reading about my problem and I am not alone

 

[WG M-B]

No it can't. Mb sell the linkage repair kits for the motors. There are x2 different kits available. It may be the motor itself and not the linkage although the linkage is more likely.

 

[Alex Crow]

As above, bang on.

I find that you can usually tell by the frequency whether it is the arm or motor - knocking every 4 or 5 seconds or so is the arm, every 1 or 2 seconds or less will be the servo motor.

I have done 3x in the last 2x weeks, 2x had broken arms, 1x was the servo, all were for footwell flaps.
Will probably go 6 months without doing another now, that's how it seems to go.

 

[pmeatonmobile]

Ref knocks

I have ordered a new flap motor for the flap just left of the heater controls as this is where the knocking is coming from. I will fit later in the week however my Texa scanning equipment tells me there is a footwell door motor with mechanical failure. Code B15A8. Please Alex is the footwell motors high up on the dash like the one I am changing or do you feel I will need to investigate more?

 

[Alex Crow]

If the motor is OK, you just wasted some money there!

If you have the standard climate, without LCD display, there is just 1x motor.
If you have the automatic climate, with LCD display, there will be left and right direction control, which means left and right footwell flaps are fitted, and you need to find out which one is playing up.

I will assume for now that you have the former.

You will need to remove the center arm rest (complete).
The center console.
The entire glovebox.

This will give good access to the motor. If the arm is broken, they are available on their own from MB for sensible money.

There is an excellent DIY guide on benzworld, complete with pictures.

 

[pmeatonmobile]

Knocks from dash

Thank you Alex for your useful reply. Like I mentioned earlier I have already removed the centre console to give access to unsecuring the glove box and removing the flap motor that is giving the knocks. The plastic arm is in great condition and I suspect the flap motor, which new, I am fitting tomorrow. This Merc 240 is a early model year 2002 so maybe the split type you mentioned but the code relating to a floor well flap motor? All I ask is are the floorwell motors near the floor and if one was not mechanically operating would it cause knocking from the flap motor high up LH of the heater controls?

Phil Eaton

 

[pmeatonmobile]

Thank you for your help. Please can you tell me how many flap motors are fitted to a 2002 Merc CLK 240 3 door? I am replacing the LH to heater controls. The only one i can find.

Phil Eaton

 

[pmeatonmobile]

Knocks from dash

Thank you Alex for your useful reply. Like I mentioned earlier I have already removed the centre console to give access to unsecuring the glove box and removing the flap motor that is giving the knocks. The plastic arm is in great condition and I suspect the flap motor, which new, I am fitting tomorrow. This Merc 240 is a early model year 2002 so maybe the split type you mentioned but the code relating to a floor well flap motor? All I ask is are the floorwell motors near the floor and if one was not mechanically operating would it cause knocking from the flap motor high up LH of the heater controls?

I maybe Jnr on here but I am 30 years Pro in the real non cyber world, please don't call me DIY!

Phil Eaton

 

[Alex Crow]

I maybe Jnr on here but I am 30 years Pro in the real non cyber world, please don't call me DIY!

Phil Eaton

Not sure who called you DIY, but it wasn't me.
I did make reference to a 'DIY' guide, as I thought it would be very helpful.

The answers to all your questions can be found in the following links, if you only bother to look at one, make it the first one...

http://www.mercedestechstore.com/pdfs/507 Systems I/507 HO HVAC 203 & 463 (ICC) 10-30-02.pdf
http://mbworld.org/forums/c-class-w...epper-motor-replacement-clicking-hissing.html
http://mbworld.org/forums/c-class-w...emoval-stepper-motor-linkage-replacement.html

 

[pmeatonmobile]

Knocks from dash cont.

I am so sorry Alex for reading your post in the wrong light - I was drunk and you have only been so very helpful so please forgive me. I am human

This is the situation I find myself in at the present moment. Reference the CLK 240 2003. The glove-box, central fascia, inc radio appeture, RH lower fascia is removed and the speedo unit. The 2 codes recorded before repair was B1598 but this was a memory fault and B15A8 LHF floorwell control flap mechanically seized was present time and this is where I feel the intermittant knocking is coming at this time. As you will know, it is also deeper behind the LH side of the heater controls than the flap-motor I previously thought was the problem. To gain access do I have to remove the upper section of the dash or is it easier to remove the LH side of the heater blower area?

Also flap motor I ordered from the MB number written on the old unit has been modified yet the MB Parts Dept. locally did not pick up on this till I questioned the nice fellow later.

Tomorrow, Saturday I will be opening at 9am and if you can help with my problems in anyway then please call me 01582 452113 or thread me on here and I will visit at 10.30am at tea break? Please look at this opportunity to advertise and show on some repairs good specialist knowledge is vital but also as a good company you can share your experience.

Sorry again and thank you if you can help further.

Kind regards

Phil Eaton

 

[jpowell79]

the knocking from my car seems higher up in the dash.......like from near the battery in the engine compartment.

Does that mean that to get to this I have to take off the entire dash (and not just get to it through the glove-box) ?

thanks

 

[Alex Crow]

...Does that mean that to get to this I have to take off the entire dash (and not just get to it through the glove-box) ?

thanks

Yes, it sounds that way, but do get it diagnosed properly first!

A Star test will fairly quickly show up the defective one/s, or for DIY remove the charcoal filters and try to see if the flap inside moves when you press the charcoal filter button on the control panel.

 

[jpowell79]

Yes, it sounds that way, but do get it diagnosed properly first!

A Star test will fairly quickly show up the defective one/s, or for DIY remove the charcoal filters and try to see if the flap inside moves when you press the charcoal filter button on the control panel.

Interestingly, the rate of the knocking noise alters when I press the charcoal filter on.

When I press it once, the knocking is every second.....press it again and it's every 2-3 seconds.

Am guessing it must be that that's causing the noise then? So maybe reaching it through the glovebox might be an option?

 

[Alex Crow]

... So maybe reaching it through the glovebox might be an option?

Sadly, no, not the one for the charcoal filter.

 

[jpowell79]

Sadly, no, not the one for the charcoal filter.

Bugger....whole dash out it is then :-(

will live with it for a while till the weather gets a bit warmer, then give it a go one Saturday afternoon.

cheers

 

[jpowell79]

Had the car connected up to an autologic code reader.

It came back with the following:

B1590 (9590) [Current and Stored] Activated Charcoal filter flap adjustment motor (A32m2): Component is stiff or blocked

B15A8 (95A8) [Current and Stored] Foot well flaps actuator (M2/15) (Left/Right): Component is stiff or blocked

B15B0 (95B0) [Current and Stored] Foot well flaps actuator (M2/11) (Right): Component is stiff or blocked


What I don't get though is that there's no knocking coming from lower down under the glovebox? Only at the top (where the charcoal filter thingy is)

Are the two connected in any way?