Mercedes-Benz R170
heated seat repair

SLK This story illustrates, how to repair a dead seat back heater element in a 2001 SLK230 Kompressor.
Seat belt bolt cover The first step is to take the seat out from the car. The seat is mounted in the car with four bolts. In addition to these, we need to disconnect the safetly belt from seat. The belt is connected to the bottom of the seat. Open the cap with a small screwdriver...
Seat belt bolt ...then open the bolt with a 17 mm wrench.
Wires under the seat Under the seat there is a module with a bunch of power cables. The center one is for heated seats...
Wires disconnected ...Unplug all cables.
Bolts behind the seat Move the seat all the way to front and up. You will see two Torx bolts on the rails behind the seat. Open these with a Torx External socket. If you do not have Torx External sockets, you can also use a hex socket.
Bolts in front of the seat Move the seat all the way to back. You will see two Torx bolts on the rails in front of the seat. Open them and lift the seat out from the car. Since SLK is convertible, you might want to take the top down before you grab the chair. That will help you quite a lot.
Module under the seat Place the seat on its side and open the screws holding the electrical module under the seat. You can leave it hanging there. The reason, why you want to unmount it is that if will give you a little bit extra power cable, when you start working on the heater element.
Seat leather Next we move to removing the seat back upholstery. Please notice that probably you will not need to remove it completely. Opening the leather from the bottom of the seat back will be enough. The seat leather sits in between the seat frame. Pull it carefully out from the slot, starting from the bottom.
Wool padding When you remove the leather, you will find a wool padding. The heater is a thin wire running inside the wool. The reason why the seat heater dies is that the thin wire breaks. Finding the problem is relatively easy...
Problem spot ...The broken wire will burn a small brown spot on the wool padding. You can open the wool padding a bit more to see the wire properly. Fix the broken wire and test the heater element with a meter from the connector under the seat. If the resistance is fine, the seat is now perfect again!

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