Yeah well i already have the horse hair pad and all the springs etc, finding another seat is not worth it for me. I already have tennis balls and pool noodles stuffed in there, but its not really that good, i figure i have the right stuff why not just fix it right?

Marybeth has the right procedure. I would say more like two hours for the first one. But after that you'll pull the second one out in 15 minutes or less.

Removing the seat belt slide makes getting the seat out of the car much easier.

As others have mentioned you'll want a 12V battery or moderate amperage power supply handy to move the seat back and forth to remove the bottom from the electric base assembly. There are a couple of holes to line up for that center bolt.

The bolts for the seat -> base are Phillips head and probably assembled with blue Loctite. Heating them up to loosen the Loctite can be a pain and a fire hazard and so figure on using lots of oil and elbow grease and probably stripping one or two. Have a bolt remover handy. I replaced all of the bolts with Allen cap heads. They are standard 6mm size and your local hardware store should have them in stock. Your standard "T" handle Allen wrenches will fit even through the base bottom beam into the center bolt.

As was mentioned the hardest part is getting the power plug undone. While trying to pry it apart the top and bottom generally pop off before it comes apart. Everything snaps back together so don't let it both you when it all falls apart .

The main plug is in a 2x4 row of pins. Each "2" sets of pins are for each axis. + on one side and - on the other for one direction and reverse it for the other.

The cardboard like fiber material on the bottom of the seat cover that goes into the lip around the bottom edge of the seat tends to start falling apart at the age of your vehicle. Be careful when pulling it out. Consider having some plastic handy to reinforce it when you reattach the cover.

Also have a shop vac handy to get all of that darn horsehair out of the carpet under the seat.

If the plastic has been broken on the end of the seat belt receiver slide it can be difficult getting it into the front receiver on the seat base. Just take it slow and easy and it will go in eventually.

Good luck!

That would be dandy........except for the fact that there is nowhere to attach the leads other than the plug. You'd need a proper wiring diagram for the seat to know which leads require power and ground.

The SD has a place on the motor to clip the leads..........the SDL does not.

Each of the three different electric motors for the seat base have their own seperate plug connection to the memory module. With the chassis harness disconnected and the seat out of the vehicle any of the three base motors can be indivdually operated by unpluging its respective connector and then using a jumper to directly apply 12 volts. Each connector has four male contacts two for electric motor power and a second two that provide position infoormation to the memory module. If you have a couple of female contact pins with 6" of wiring attached you just need to connect these to the two power pins, apply 12 volts, if the seat base moves the way you want it your in business, if it doesn't reverse the polarity and it will!

The 6 large philip's head screws which hold the seat motor base to the underside of the seat spring are best removed using a hand impact driver and a mallet. A short, sharp shot or two easily breaks the loctited screw free without damaging the screw head. This allows not only the removal of the screw but it's reinstallation .

If you're working on leather seats it is a good idea to apply some conditioning product to the seat cover first, one area that is usually quite dry and is prone to tearing when removing a bottom cover is the leather around the semi-circular cutout around the seat back hinge. There is no reenforcement or stiching along the leather's edge and often times a tear will form there when the back edge of the seat cover is released first. So when removing a bottom cover release the side and front edges first then the rear to avoid this potential for damage.Good Luck!

Are these the small four pin connectors...........not the single large connector?

Is there a way to know the power contacts for the motors on those connectors?

I found on my SD 83, D 85 and SDL 84 the purple and blue wire controlled the seat slide forward and back.
12V+ Purple wire & 12V- blue wire= seat motor forward
12V- Purple wire & 12V+blue wire = seat motor back

Your results may vary

Under the driver's seat is the memory module, at its front top edge it has connections for the seat switch (a 14 or 16 pole rectangular connector shell), the power connections (a 4 pole square connector shell), and a second square connector(this has the head rest control and something else I don't recall at the moment, in a four pole square connector shell), at the rear of the module are four square four pole connectors, one for each of the seat base motors and one for the seat back motor.

Each of these motor connectors has four conductors two are power to the motor and two are position info from the position potentiometer attached to the motor shaft. I don't have one in front of me at the moment so I'm not certain but I seem to recall that there are two different gage wires used for the two functions, the heavier gage for the motor power and the lighter gage for the position signal. There may actually be different size electrical contacts in the connector shell, I just can't be sure at this moment. One can easily look at the wiring coming from the electric motor and note the color code then open the four pole connector shell and note the position of those wires.

It is not the easiest but I have on numerous occasions; usually when a switch, memory module, or wiring has failed, reached from below and behind the seat unplugged these individual motor connections and used jumper wires and a 12 volt source to move the seat base enough to access the 4 bolts securing the seat base to the chassis. As a result I've also constructed an abbreviated wiring loom with a seat switches , power, and ground connections that can be used by unplugging the vehicle's seat wiring harness at the front of the memory module and plugging my setup into the module's connections then attach power and ground sources. I can then hopefully move the seat independent of the vehicle's system; this is also an easy way to begin the diagnosis of seat switch and seat switch wiring issue possibilities. If the seat still does not function properly it’s likely a memory module, motor or cable issue inherent to the seat or its' base itself. This setup also works great if you’re ever retrieving seats in a bone yard. I've used it to test some extra seat switches for functionality also.

Early 126 chassis vehicles without seat memory function are wired directly from power/ground, through the door mounted seat switch to the seat motors. In this case the connection under the seat can be unplugged and power and ground applied to the particular pair of wires and a functional motor can be operated. Wiring for the motors is like colored wire pairs i.e. purple/purple-white striped and located in parrallel adjacent pairs 1/2, 3/4 etc. in the connector shell.

124 chassis seats have a couple different generations ending with the last generation having the integrated convenience module and integrated micro switch controls, but the first generation is similar to 126 Gen II.

Hope that clarifies things, good luck!

Brian ---- I traced them and figured it out one day.........Let's just say it was AFTER my memory board quit working in the car.

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daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
Cluster Needles Paint
New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

Gentlemen,

While on the subject of seat electrics, I replaced the front drivers seat on my 1987 300TDT with a leather 1993 seat. The connectors plugged right up bu now the head rest does not respond to the switch. I believe one of the connectors on the 1987 has an extra wire. I do have the manual for the 87 but not for the 93 so I'm unable to compare the circuits. Does anyone have a seat circuit diagram for a 1993 300TE that could be made available?
Can it also be possible that since I did not replace the driver's seat the system is "confused"?

Thanks for your help.

Lino

Thanks BB.........I'll be saving that for future reference.

Great instructions and a wonderful sense of humor!

You Rock!

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Bama1


2008 SLK 280, Firemist Red - "Hurricane"
2001 F150 Lariat 4x4, Black on Black - "Badboy"
1982 240D 4 speed survivor -"Pearl" - Donated to Vietnam Veterans
1962 Oldsmobile Dynamic 88 -"Gertrude"

1954 model original owner - ~2.5M
Gray softtop/solid exterior/modified chassis

while we are all on the subject-does anyone have a list of which later model set frames will fit early model seat rames/

Example a 1997/98/99 drivers Seat frame from a XXX MB will fit a drivers 1983/84/85/86 XX MB

does anyone know where i can find a link with pics for DIY job? of the seat cushion and spring installation

Zombie thread, back from the dead. I'm curious about this as well as any possible manual seats from the newer years, do they even exist?

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82 300SD