airscarf clarification

The heated seat element is a common issue in our cars and shockingly most of the MB lineup from the early 2000s up until 2012. There was a stickied thread on this issue in the R171 General Discussion on this topic in the past, not sure where it has gone. Use the search feature, should be easy to find.

In regards to the airscarf, seeing as all the components live in the back of the seat you need to remove the seat itself to work on it effectively. Removing the seat itself is not hard, and neither is exposing the components, diagnosing the exact faulty part may be an issue though. Since you plan to hand it over to an automotive electrician and in the scheme of things the airscarf system is *relatively* simple(ish) once the seat is out it should not take too long to diagnose the faulty part.

Worse case scenario is that you may need to take it to someone with DAS and see if it is a control module issue... but hopefully that will not be necessary if it is just a faulty part.

driftaround said:

Hi all. Had a long, fruitless search through the posts for a definitive answer to my query before asking other members. I'm hoping I can get some specific advice or pointers to make the issue as easy as possible.

My airscarf switch for the drivers side has 3 led lights that show when the button is pushed, but then go out after a few seconds. Reading a post from Seanhump it mentions that a 3 led that then goes out, without flashing, indicates nothing coming back from the seat. I'm assuming that the airscarf is a pretty rudimental bit of kit, with few parts, so not too difficult to point to any common problems, others have had.
I can't do it, but I'd like to give an auto electrician a guide as to how to narrow possible problems down. For example, is it easier to remove the seat? Is it a coincidence that the drivers bottom heated seat element is also not working? is there anyone who has had, and solved, the same problem?

Any and all help is appreciated.....
Ian

Click to expand...

Under your driver's seat (accessable from the front) there is a black electrical connector which has four wires - two are for the airscarf heater, two are for the airscarf fan motor. If you know how to use a multimeter you can test the continuity through the heater then the motor, and compare to your passenger seat. I'm betting that either the heater or the motor are open circuit and thus need to be replaced.

If you are interested in tackling this I can upload the wiring diagram and instruct you on what to test. I can also upload the instructions on how to remove the airscarf unit if you want to do this. It's very easy, but I don't know your competency level.

Whatever you do, do not disconnect the yellow connector under the seat as this will trigger an SRS warning light on your instrument cluster.

driftaround said:

thank you all, for your help.

RJV, I would like the wiring diagram and instructions please, it would be a big help. Happy to receive via here or my personal email.

Seanhump, the seat back removal seems easy enough, so does the switch testing, thanks to the original post.

Akonion, do you suggest DAS first, or the continuity testing?

Ian

Click to expand...

OK, here are the instructions to remove the seat back and the wiring diagram for airscarf (and seat heater pads).

On the wiring diagram locate M4/11 and you will see the fan motor and heater element in your right seat. Locate X55/4 which is the black connector under your right seat. Look at the wiring above X55/4. The brown wire and red wire connect to the fan motor and the blue wire and green wire connect to your heater element. Unplug the male side of the connector (which come up through a hole in the carpet from the female side of the connector (which is clipped to the under seat frame) and with a multimeter test the continuity across the fan motor and then the heater element by probing the female side of the connector. Make a note of the resistance in both, and then compare these to the readings on the left seat.

On the faulty (right) seat I'm expecting that either the fan motor or heater element is "open circuit" (i.e. infinite resistance). My bet is that the heater element (blue to green wires) is open circuit.

Before you start doing nasty things, do something simple (5 min. job).
When the Airscarf is used intensively for prolonged periods of time, the wiring may simply overheat. As a result, it MAY be the case that the feeding plug has melted (resulting in a short circuit).

In my car, this appeared to be the case. I did not realise until I had read a posting on a German SLK forum.
The solution? Instead of swapping the super expensive Airscarf unit, all it cost me was some EUR3.50 for a new plastic plug housing.
Part no. is A0465458228.

The plug feeds underneath the seat, and you do not even have to take out the seat (I only put it into its highest position, and as much to the rear as possible).
Below is a pic of the melted plug housing.

Arjen.

The melting plug is on the feeding wire (hence, the car loom). On my LHD car, it is the plug located on the outer side, bottom of the seat (front side).
See some of the below photos.
If you have the memory seats (like I do) then you will see three plugs. The black one on the below photo, next to the yellow one for the airbag, and another separate black one for the memory seats.

The first below photo shows the plug when still mounted.
In the second one I took out the Airscarf wiring plug (clicked into the larger one). In my case, all I had to do was putting something thin into it (flat blade screwdriver, or tie wrap) to loosen the pins.
Next, I bought the new small plug housing, of which the third photo shows the opposite side of what you see in photo 2.

Really, it is a 5 min. job to check and (if needed) repair this.

Arjen.

Eureka!!!! :laugh:

Plug was making a short circuit after melting!!
Thankyou Arjen.
From the back of the plug, all looked ok.
After disconnecting it, it was easy to see that the centre part of the plug had melted, allowing the shorting.
New plug on order, but lets hope its acted as an RCB and nothing else is fried.

Just one more thing Arjen, how do you get the offending plug out of the loom?
I thought it would just click out, but not so.

Ian

unkellsam said:

Thanks Arjen,

This was the same problem for me too on an E350. However, not only did the plastic housing melt in the front seat, but also after the fuse box in the trunk. So if anyone has an issue where the Airscarf on both sides stops working, check the trunk for a short as well.

Does the A0465458228 part you referenced include both the male and female parts of the connector, or just the male?

Click to expand...

FYI Arjen has not been on since: Last Activity: 01-28-2017

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