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1992 300E 2.6
153 Posts
Discussion Starter #1
Since this was the first car I've ever owned that did not have heated seats, but was able to have them from factory, I knew I had to make the install happen as cleanly as possible. It took some research and scouring for parts, but I was able to complete it fairly easily and problem-free. From start to finish, the whole process should take about 8 hours if you're somewhat familiar with how this should go/have the tools and take your time.

For a 1992 300E, this is what I needed to track down:
4x Seat heater pads for MB-Tex/Velour: A0008202198 (The pads have the pins already soldered to the leads)
2x Pad Connector Housing: 0095455228
2x Pad Connector Cover: 0095452128
1x Primary harness: A1245403813
1x Power harness: A1245406435
1x Control Module: A0008206226
2x Control Module Securing nuts: N9130111006000
Heated seat switches
Woodgrain panel to match your switch clusters

If you do not have the auxiliary fuse holder on the Drivers side strut tower already, you will need the following (Not my picture, another members' here):

Tools Required:
10mm box wrench/socket
Phillips and Flathead screwdrivers
Needle nose pliers
Soldering iron-not needed but recommended to change the heater pad pin orientation from top, to side
Razor blade

All photos will be at the bottom of the post

So the process to make this happen is pretty straightforward, in its simplest form:
-Disconnect Battery:
Use a 13mm to loosen the negative cable and remove from battery.
-Remove the Front Seats:
4 10mm bolts at each corner of the seat base, and 1 10mm bolt securing the seat belt buckle to the shaft tunnel.
Unplug existing wiring from the front of the seat base
-Remove Front carpets:
Pull up on the two clips at the rear of the carpet sections and maneuver out of the car
-Remove rear seat bottom:
Push-in the two orange clips at the front of the cushion and lift up and towards the front of the car
-Remove the dead pedal:
1 Phillips screw at the mating point of the door sill and two clips towards the pedal cluster
-Remove bottom plastic panel from above pedals:
The black plastic panel above the pedals should have two screw at the rear end securing it to the car, mine did not. To remove the panel, you will need to maneuver it out with bending and contorting
-Gain Access to the underside of the fuse panel:
Take the panel cover off and remove the 6 phillips screws holding the top cover in place. Remove the 1 screw holding the fuse holder down and lift up and away
-Remove Drivers side B-pillar cover:
2 phillips screws at the base of the panel, it pulls away fairly simply
-Remove center console or enough to route wiring:
This will differ depending if you have the storage box or not, after it is remove via the 2 phillips screws on the forward end, remove the 1 phillips screw at the rear of the console. Remove the 1 phillips screw from the rear of the wood trim. Remove the trim around the shifter by pulling upwards. Lift the window switch cluster up and away.
-Remove the door sill protectors:
These are held in by clips on the underside, if you have a trim removal tool, this is its moment to shine. Other wise a rag and a small flathead can be used to pry up as close as you are able to the clips as possible.
-Remove the rear floor vent:
There are 2 phillips screws keeping the vent to the floor, remove them and pull straight back to get the vent out.
-Lift up carpet from driver's side:
Now with all of the above removed, you can lift the carpet out of the way.

-Take the primary harness and lay it in the cable runs as best you can. In order to get the cable to the passenger side, I was able to run it up and over the tunnel without removing the console entirely. The forward end plugs in at the junction block under the dead pedal as outlined in the below pictures, the rear is brought up to the control unit via the passage in the metalwork. Remove the comfort module and install the heated seat controller with the two nuts. I laid in some vacuum line and a power wire (disconnected) if I ever install Orthopedic seats.

-Once this is done, you can re-install the interior up to below the dash.

-Run the power harness from the junction block, up through the fuse panel. Once it is up to the panel, feed the two fuse wires out of the box via any weather-proof location and out to the strut tower to be inserted into the holder. Once this is done, attach the re power wire to the appropriate lug above the interior junction block.

-Once this is done, you can close-up the fuse panel and the underside of the dash. At this point, only the seats should be out of the car.

Now the fun part: Installing the pads

I recommend taking the seats apart on a clean carpet in a house, or somewhere similarly clean and not likely to damage the seats. Disassembly will require removal of some old plastic parts, I cannot stress enough to be careful with these, take your time, and do not force anything.

Seat back:
-Start by removing the plastic covers at both sides of the seat back bottom, be gentle and work them out slowly. The outer cover has two sets of clips at the forward end that must be squeezed from the top and bottom to be released.
-Remove the fry catcher by pushing in on the two black plastic nubs until they disappear into the seat-you will need to shake them out of the seat. The fry catcher can now be slowly pried off the base.
-Now remove the two phillips screws at the bottom of the seat back. From here, the seat cover is secured around the left and right side of the rear cover by a rigid edge curled into the edge channel. (If you look at the bottom end, you can see how it works. You need to lift this rigid edge out of the seat back cover and peel it outwards.
-Next, remove the headrest by pressing the small button on the guide track and pulling it out.
-The seat cover is held in place by 9 metal rings and plastic clips that slide into the rings. These simply slide out when the seat cover is pushed in from the front.
-Near the top of the cover, there is an elastic band around a plastic bracket, use the pliers to grab this and slide over the brackets hooks.
-At the bottom of the cover, you will see another reinforced edge that is slid out in the same manner as the back cover.
-At either side of the bolster, you will see a hole in the seat cover secured over a metal hook, slide the cover around this.
-You can now remove the seat cover and flip it backwards over the seat back, stopping at the headrest holes. You DO NOT need to remove it any farther.
-The existing seat padding fingers are slid into pockets of the cover, and sewn in at one end. Cut the thread on this one end.
-The seat heater elements do not run the full length of the grey fabric area, you can see where they stop if held up to light. For this reason, they must be inserted with the leads at the bottom of the seat back, with the grey facing the MB Tex.
-I used a piece of vacuum line, inserted from the end where the thread was cut, to pull through the heating pad fingers. The fingers must lay flat against the existing padding, pulled all the way through until even with then portion of the seat cover pleating that is sewn in. DO NOT pull tightly against this pleated portion, it will bunch up the seat cover and not look right as well as stress the heating pad out.
-Once the pad fingers are pulled through, you will have excess slack at the end, this is meant to be sewn into the seat cover. You either can do this, or leave it alone as I do not see these ever working their way out.
-The leads are routed to the seat bottom by following the existing wiring to a channel at the inner side of the set to the center console. Secure the lead in the seat back via the existing zip tie and route through this channel.

Once the above is done, you can re-secure the seat cover in the reverse of disassembly.

Seat Bottom:
-The seat bottom cover is held in the same fashion as the sides of the seat back cover. You need to start at one edge of the rail and work around to the other side-note that there is a metal clip at the front center of the cover securing rail. You might need to loosen the two bolts holding the seat back to the bottom assembly in order to get some slack to remove the seat bottom cover.
-Do the same as above for the back of the seat bottom cover.
-You will also need to cut the thread at the sewn in ends of the padding fingers.
-Repeat the process used on the seat back heater pad fingers, leaving the leads at the back of the seat cover and also DO NOT pull the fingers tightly against the sewn in pleating.
-Lead the wiring leads down through the hole in the seat cushion foam to beneath the seat.

Once the above is done, you can re-secure the seat cover in the reverse of disassembly.

For the remainder of the wiring, follow the existing wires in the seat base and secure with the existing zip ties, or use your own. You will have some excess wire that needs to be secured, you can either zip tie it out of the way in the seat, or cut it to a shorter length.
The location for the plug is on the outer front corner for the drivers seat, and the inner front corner for the passenger seat, so route accordingly.
There is a cut-out in the seat base sheet metal the proper heater pad connector plug back cover locks into, it is obvious to look at but shown below in the pictures.

Once you have all of the above completed, re-install the seat into the car and test your work.

The comfort module, beneath is the heated seat controller:

The channels beneath the drivers seat and console:

Everything in place to plug into the seat:

The junction block:

The auxiliary fuse holder and power routing:

Feeding through the fingers:

The plastic clips:

The elastic band:

The seat pad plug in place:

I have a few more pictures I did not upload if anyone needs, if there are any errors here or questions, please let me know.

2 Posts
Excellent work and write up! I have the same project in mind, all parts collected except the grey leather with the seat heating elements (they’re sewn in).

1992 300E 2.6
153 Posts
Discussion Starter #3
Excellent work and write up! I have the same project in mind, all parts collected except the grey leather with the seat heating elements (they’re sewn in).
You can always do a two-part installation, lay in all the wiring and components and once you get the covers you have that much less work to do.

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
12,756 Posts
Great job Joey and an equally great write-up!


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