Stepper motor

[map747]

Hi folks.

Had an issue with my ML55 in that clicking noises could be heard from behind the centre vents. The upshot was that according to the STAR the motor that controls the centre flap was faulty. So i purchased a new one and managed to fit it myself....no easy task with the airbag etc still in place... put it all back together and guess what????? Yip it still does the same thing, clicks and pops but eventually settles down.
Any one else had this issue after replacing this particular motor?

Thanks.
Martin.

 

[Stratman]

It's just a guess, but there may be some synchronising process required after a replacement. I believe there's a 'Vulcan Death Grip' series of button presses on the A/C control panel which resets everything.

Hopefully someone who knows will pop their head in.

 

[grumpyoldgit]

Not sure if this reset will work on ML's.


To reset heater flaps and actuators

Switch on ignition.

Press recirculated air and defrost buttons on control panel together for longer than 5 seconds.

The LED's in the defrost and recirculated air buttons flash alternately.

Wait until the LED's stop flashing (approx 30 sec) system set to defrost LED on.

Switch off ignition.

After 40 sec re start engine.

 

[Lyserman]

If what Mike says above does not work the a session on STAR is required.
It has to set up so the system knows where the fully open and shut positions are using a normalisation procedure.
They are called stepper motors because they move in small steps and the system counts the number of steps from shut to open and the start and finish point so it can set the flap in the required position.
There is a specific section within STAR for this and anyone competent with the system can do it in 10 minutes.

Tony

 

[map747]

Thanks for the replies.

Tried to reset the system using the defrost etc. But to no avail.
The flap just seems to continually run through its cycle.

Thanks again.

 

[lexman8]

As above, I'm pretty sure a new stepper motor has to be normalised on STAR.