Possible heating issue with ML270

[sturgeon]

Its def electrickery. The ECU must sense the resistance/impedance/reluctance/capacitance or one of the other 'tances.

Polish up your wand!

 

[Joderest]

I have researched on the "net" and it seems there is no definitive answer, some say has to go onto star after a replacement, some say it does not

 

[Joderest]

Well. i am getting good at this.
Took 1/2 hour to strip out and get at motors, easy once you know what you are doing. why Mercedes quote 5 hours plus is beyond me.
Anyway, i still cannot work out how these motors know when to start and stop. I played with the other one that does not work this morning, directs air to rear heating. it just will not do as controls are telling it to.
I now wonder if there is something else not right, and if the connections to the flaps are out of positions, perhaps spun on the shaft when motors went out of range. I only think this as looking at the lower flap arm, it does not fully open when the lever is at its fullest extent, about 1/4 way to go.
I will keep trying, but it is beating me.

 

[sturgeon]

Keep at it! You will be the forum flap Guru after all this!

And - think of all the £160 hours of labour charges you've saved!

 

[Joderest]

I agree, but with two replacement knees, and two rods and six screws in my back, it hurts after a while !!!!!!!!
Should have kept off the Rugby and Football fields !

 

[SL300-24]

Turn the ignition on but do not start the engine, press and hold the auto button for 3 seconds and it should reset the flaps for you and give you heat at the windscreen.

 

[Joderest]

hi SL300-24 tried that, no luck.
UPDATE
well i fitted the new motor, connected it all up, turned it on and it all worked as it should, once !!!!!, then has gone back to open/close/open/close/open etc etc etc.
I really am well and truly beaten on this now. Its all back together. I have contacted a mobile Mercedes tech and spoken to him, he said that sometimes the car needs to go onto DAS and STAR to reset the motors limits, he said that sometimes its plug and play and sometimes its not. I am taking the car to him on Wednesday as he is at his work shop and its only about 45 mins away, and he will have a look and see what the issue is.
So at the moment i am £140 plus poorer, and still no defrost air, well, it does, it does not, it does etc etc etc. He also mentioned that if there are stored or live faults on the AAM, this would prevent the motors working as they should. I cannot find the system on the MB2, so not sure if it can access the A/C system. I will also ask this question.
Of course, for closure i will keep updating this, may help someone else one day (wish it was me !)

 

[Joderest]

UPDATE and hopefully the end.
OK, took car to MB tech. He plugged STAR in and on A/C system there were two stored and currant faults. Both were on the actuators I have had issues with, defrost flap and rear air flap.
He did a reset, cleared both faults. Its now all working as it should,all the way home. What a relief not to have to keep wiping screen or driving with window open, and I was warm.
So, despite what I have read, it appears that a reset was required. He actually stated it may have not needed a new actuator, but hey ho, its in there.
One thing, told that its a good idea to go in there and put some grease on the linkages once a year or so, as they dry out due to heat, will be doing that in the summer.
Now back to simple jobs, like sorting out sticky throttle pedal.
Thanks for every ones help and comments.

 

[sturgeon]

Excellent! Glad its sorted, you can give your knees a rest now!

 

[Joderest]

I have done some digging.
It could well be that the motors "sense" a resistance when they come to the stop, which in turn tells the ecu to shut power off, hence the learning of the stop position. If the linkage gets dry, it could cause the arm to "bind" giving a false stop location as motor will sense the resistance, and due to this, they system will get out of limits, hence causes an issue.
i cannot understand what was wrong with cables to turn flaps !!!!, oh well, progress i suppose.

 

[Joderest]

Oh bu**er, i am really starting to dislike this car !!!!!!
Ok, for a week everything was fine, then today, on way to work, no heat to windscreen again !!!!!!!.
When i got to work, turned car off, re started it and lo and behold, screen air worked. tried it again, and it worked. Left it for 10 mins, tried again, no air to screen, turned blower up to max, and the flap opened !!!.
I have found, in the car, tiny bits of foam rubber that is blowing out of the vents, its very sticky. What i think is happening is the foam has started to come away from the flap, leaving the glue behind, when the system turns off its default is windscreen vent closed, i think its sticking shut due to the sticky foam.
This would be the reason for the arms splitting as motor is quite powerful. At the moment, only true resolve is to take out heater box, a two day job !!!!!
However, my auto electrician has a small camera on a stalk, like a probe, we are going to stick this down the heater outlet to see what is going on, and if at all possible, try and clear what ever is sticking the flap shut.
wish i had kept my landrover !!!!!!!!

 

[wu56Shoozz]

Now, I'm not saying that this is correct..

I had this on another vehicle with a similar situation and I found a thread that says that the system must relearn its settings, and to do this you had to remove a relay in the fusebox then set it to ignition and you would hear the car "buzzing" away as it ran through its checks of the system.

It may be similar and that you need to find out if it has this facility, then execute..

 

[Joderest]

Wu56shoozz. Thanks for reply, they have recently been reset by Star.

What we are going to try is having a look with an endoscope, and if it is the remains of foam on the flap sticking it shut, we are going to try spraying silicon on the foam which should stop it sticking.

Sods law, it all worked perfectly on way home tonight. I have collected about 5 bits of foam the size of a 1 p piece, and I have already checked 5 more away before I realised where it was coming from

 

[wu56Shoozz]

An idea... look for a heater box from a breakers, carryout the repair on the "new" one then when ready (better weather) swap over - job done?

 

[Joderest]

yes, i did think about a 2nd hand heater box, looked on e bay and could not find one, only rear ones.
I would rather not do it as its all of the dash out to get at the box, looks like a weekends work, and at the moment have better things to do than strip car down.
It all worked again this morning, all be it i had to put blower on max to open windscreen heater flap, if must help with air pushing against it and unstick the thing, once opened, every thing works fine. I am convinced its the reason the actuator arm and motor packed up, flap stuck down, motor spins in flap and splits it, motor then well out of position.
as always i will update outcome

 

[sturgeon]

Is there any way you could get something on it to unstick the sticky area - like talc? - although you'd then get that blasted all round the inside of the car. Silicon spray? (don't breathe it in) Something?

 

[Joderest]

Sturgeon, thanks, but have tried with silicon spray, got flap to open, min blower and sprayed, hmmmmm
First start in morning does not open, stop, shut off, restart, it opens and works fine.
then it will not open again on next start, repeat process, fine.
I am really starting to give up and looking a Kia Sorento's (god help me).
I suppose next step is to have open wallet surgery.

 

[Joderest]

I have even suspected the AAM, but every thing else works fine, and the fault is so vague, no one seems to know why its doing it, auto electrician, stumped, Merc tech, Stumped, me even further stumped.

 

[skippyjasper]

"I suppose next step is to have open wallet surgery."

Thanks for the chuckle.

 

[sturgeon]

Right pain every step of the way isn't it! Is it worth squirting some silicon spray into it when the flap is closed/set the other way/s incase its sticking somewhere else? We had our ML270cdi for 6 years and it was brilliant despite the odd foible. Worth persevering I think?