Installation instructions – seat occupancy sensor emulator – Mercedes

Seat mat emulator Mercedes - installation

1. Turn the ignition off.

2. Under the passenger side seat find the seat occupancy sensor connector.

Seat occupancy sensor wires colors in different versions:

  • white, red, brown (the most common three-wired mat)
  • black, black (two-wired mat)
  • blue, brown, black (in some newer models)
  • white, red, brown, green (in some american US version models)
There are different types of plugs in different models, which is why we present pictures from different Mercedes models in the next part of the instructions.
 
3. If the emulator is ended with a connector, just disconnect the seat mat plug and plug in the emulator instead.
* Before connecting the plug, make sure that the order of the wires in the emulator plug is the same as the order of the wires in the seat mat plug. Rarely, may it happen that the order of the wires in the plug is different – in this case you need to change the order of the wires in the emulator plug to the same as in the original seat mat plug.
 
If the emulator is not ended with a connector, it is needed to replace seat mat wires with the emulator wires (remove wires from the plug under the seat and put the emulator wires instead in the same color order) – white for white, red for red, brown for brown.
 
In case the seat mat has wires blue, brown, black, the scheme is as below:
Brown – brown – „GND”
Black – red – „+12V”
Blue – white – signal
 
If the emulator is not ended with plug or terminals, it is needed to use special clamp connectors or solder wires.
 
4. If a car if equipped with the unfastened seat belt warning system, install the seat belt emulator as well.
 
5. Reset the fault code using proper diagnostic software.

Click on selected model to scroll to the photos of the seat mat plug:

Click on the picture to enlarge

Above, we present pictures of a classic three-wire mat in A-Class.

Sometimes in W168 it may happen that there are five wires in the plug. Such a case is presented in the pictures below:

The emulator should be connected to three wires (white, red, brown). Two black wires leave unchanged.

View of the connector after opening. At this point, you can hear the squealing, which will disappear after closing the connector.

It is best to connect the emulator outside of the presented connector. For this purpose, cut the mat wires (white, red, brown) and connect the emulator towards the car installation by soldering wires or using little clamp connectors.
Thanks to the fact that the plug visible in the picture stays connected, the two black wires remain connected without any changes.

Click on the picture to enlarge

Connect the emulator to this part of connection. Wires colors on the side of car installation may be different. Wires colors on the side of seat mat: brown, white, red.

The emulator supplied by us has wires in the following colors: white, red, brown.
3 wired seat mat in W176 usually has wires: blue, brown, black.
This information is not important if the emulator is equipped with a plug – just unplug the mat and connect the emulator plug.

  • If the seat mat on your car has 2 wires, don’t try to connect 3-wired emulator. As it is written in the item description in the listing, it doesn’t work with 2-wired version.
Emulator plug and wires
Seat mat plug and wires

To connect the emulator which is ended with terminals (not plug), replace the wires in the plug accordingly to the diagram below:

Brown – brown – „GND”
Black – red – „+12V”
Blue – white – signal

Watch our short installation video - it looks very similar as in W212:

The emulator supplied by us has wires in the following colors: white, red, brown.
The seat mat in W246 usually has wires in the following colors: blue, brown, black.
This information is not important if the emulator is equipped with a plug – just unplug the mat and connect the emulator plug.

Emulator plug and wires
Seat mat plug and wires

To connect the emulator which is ended with terminals (not plug), replace the wires in the plug accordingly to the diagram below:

Brown – brown – „GND”
Black – red – „+12V”
Blue – white – signal

Watch our short installation video:

Below we present the connection of the latest version of the emulator – 2in1. The seat mat and seat belt emulator are put in one enclosure which is easier to hide under the seat. The seat mat emulator plug was connected instead of the mat, the seat belt emulator plug – instead of the seat belt buckle.

Click on the photo to enlarge

Watch our short installation video:

The view from the front of the seat. Mat plug on the left, seat belt plug on the right.
Connected emulators

In W204 and W212, the three-wire mat has two color versions of wires, as shown in the pictures below:

White, red, brown
Blue, brown, black
View from the back of the passenger seat. The first plug on the left is the mat plug.
The first plug on the right is the seat belt buckle plug.

Watch our short installation video:

Click on the picture to enlarge

Watch our short installation video:

View from the back of the seat. The first plug from the left is the seat belt buckle plug, the second from the left is the seat mat plug (wires: white, red, brown).
View from the back of the passenger seat. The first plug on the left is the mat plug.
The first plug on the right is the seat belt buckle plug.
The first plug on the left (yellow) is the mat plug. On the other side of the connector (not visible in the picture) the colors of the mat wires in this plug are: brown, white, red.
3 pin mat connector - wires: brown, white, red. View from the front of the seat
View from the back of the passenger seat. The first plug on the left is the mat plug.
The first plug on the right is the seat belt buckle plug.

Watch our short installation video:

View from the back of the seat. The first yellow plug on the left is the mat plug
View from the front of the seat - different wires colors
Seat belt buckle plug which is placed on the back side of the seat. Wires: yellow, blue

In ML W166, the three-wired mat may have two color versions of wires, as shown in the pictures below:

White, red, brown
Blue, brown, black
View from the back of the passenger seat. The first plug on the left is the mat plug.
The first plug on the right is the seat belt buckle plug.

Watch our short installation video - W166 looks similar to W212:

If you bought emulator ended with a plug, before connecting it, check if there is exactly the same color order of wires in the seat mat plug and in the emulator plug. Sometimes the wires order in the plug in the car was different, in this case the wiring sequence should also be changed in the emulator plug before connecting.

Seat mat plug
Seat mat plug
Mat connection disconnected
Emulators connected
The newest version of the emulator (2in1) connected

FAQ - PROBLEMS AND SOLUTIONS

In all Mercedes models, originally the seat occupancy sensor is placed only on passenger side seat. Therefore, you should look for the plug under the passenger seat, not the driver.

In different models there are different mat plugs. If you can’t find photos from your model above, see other photos – maybe among them there is the version that was placed in your car.

The seat occupancy sensor may have: 2 black wires or 3 wires (white, red, brown) or 3 wires (blue, brown, black) or 4 wires (white, red, brown, green).

If you still can’t find the correct plug, contact us and attach to your message as exact photos as you can, showing all connections under the passenger seat. Don’t forget to add information about the car (model, manufacturing year, european or US version).

Connect the seat belt buckle emulator.

Installation instructions for the seat belt emulator – click

After connecting the seat occupancy sensor emulator, the airbag control unit (and car computer) “sees” the front passeneger seat as always occupied (even if there’s no passenger).
Therefore, cars equipped with seat belt fastening sensor will report a request to fasten the seat belt (the unfastened seat belt warning light/sound appears). Connecting the seat belt emulator will solve the problem (car computer will “see” the passenger seat belt as always fastened).

Reset the fault code using proper diagnostic software.

If resetting the fault does not help make sure that the warning light is caused by faulty seat occupancy sensor – the airbag warning light indicates a failure in the safety system and it does not necessarily have to be seat mat. The seat occupancy sensor emulator bypasses faulty seat occupancy sensor only – not other parts of the srs system. Often the cause of the airbag warning may be a faulty seat belt tensioner. That can also be other parts (airbags, BST, airbag control unit etc.) or a defect in the car installation – perform accurate computer diagnostics using a good software – cheap / non-original scanners often show different errors than they actually do.

Sometimes there may be different types of mat in Mercedes and it may be necessary to change the emulator settings. If you can not reset the fault code related to the damaged seat mat, please contact us. We will need the following information:

1. Model and year of production of the car and the car version – European or American.

2. Exact codes and descriptions of errors from diagnostics before connecting the emulator.

3. Exact codes and descriptions of errors from diagnostics after connecting the emulator.

4. Transaction details so that we could find the transaction and see exactly which device was sent (name and surname or nickname from ebay or order number, date of purchase).

The flashing SRS can have many causes.

The most common reason is the airbag control unit was unlocked for programming – it needs to be blocked. Another cause may be too low power supply voltage to the airbag control unit or its incorrect coding. Other causes include, for example, a problem with the ignition module or badly erased crash data.

Read more here