W126 generation II to gen I seats swap - problem - PeachParts Mercedes-Benz Forum

1stimer · #1 09-10-2009, 11:27 PM

I wanted to change out the interior of my 300SD due to (2) severely challenged front seats, so I purchased a black interior from the junkyard. It was out of a 1991 W126 gasser. The seats went in no problem, but the wire connectors don't match up on the drivers side. I have forward and back movement luckily, but I get that when I hit the recline button on the switch. I have no recline movement, but the biggest problem is I don't have the height adjustment, and I'm sitting WAY too high. My head is hitting the sunroof.

The passenger side doesn't look like any of the connectors are going to go in.

The other problem was my friend did not want to store my original seats, so I just got rid of them on craigslist, so now I don't have access to the old motors, or connectors. DUMMY!

Can I just supply power to the motor somehow to at least get it to a more comfortable position until I can figure out how to re-wire the connections??? Will a battery charger work for this???

daw_two · #2 09-10-2009, 11:44 PM

If you decide to go the easy route and want a set of 300SD seat frames, I've got two sitting in the 82 300SD parts car. I'll be happy to sell you one cheap as the seat is not "hot". The other seat is in pretty decent shape.

1stimer · #3 09-11-2009, 09:06 PM

Thanks daw, but I'm not sure how this would be the "easy route". How would this help my problem? What encompasses the seat frame. I just took the whole seats out of the donor car...rails, frames, motors, everything.

daw_two · #4 09-11-2009, 10:34 PM

Quote:

Originally Posted by 1stimer

Thanks daw, but I'm not sure how this would be the "easy route". How would this help my problem? What encompasses the seat frame. I just took the whole seats out of the donor car...rails, frames, motors, everything.

I could send you the whole rails, frames, motors....and you could bolt your NEWish seats to them. The plugs on the rails from the 82 300SD parts car should plug right into your wiring harness. At least that is my theory --- we could exchange photos and see. Probably someone on this forum would know.

IF you had kept your rails\motors\etc. You could have mounted the seats onto your old rails.

At least that was my theory.

I used a seat from a late 80's 560SEL in my 86 300SDL for awhile.....The seat bottom and back were good and firm\strong. I mounted the seat onto the 300SDL rails, so the seat moved back and forward and height per the buttons on the door. I don't remember if the headrest was plug compatible or not.

1stimer · #5 09-12-2009, 11:31 PM

I might want to try this. Can anyone confirm that this will work, and what my other options might be?

Brandon_SLC · #6 09-12-2009, 11:57 PM

Easy fix,

pawoSD · #7 09-13-2009, 01:02 AM

When I did this on my car I rewired the GenII seat entirely to work with my older GenI wiring.....the new seats had memory functions and everything. I removed all that and re-did them to match the old setup. Lots of soldering....and I "lost" power headrests....but I have the wires laying under the seats, so should they ever need to be adjusted (unlikely) a 9V battery or a cord to the power outlet in the car will do the trick.

ARINUTS · #8 09-13-2009, 01:10 AM

Since your old seats are gone, I would go back to the yard and snatch at the very least the connectors / plugs , and I would try to get as much as the harness as possible. then you will have to figure out and splice!

1stimer · #9 09-13-2009, 01:53 AM

Quote:

Originally Posted by Fisherman

Is really not that hard. The "inaccessable" screws that moutn the seat frame to the base can be accewssed by using a small screwdriver in the opening in the motor end and turning the motor to move the seat on the base to lineup the hole to access the screw... Did tht make any sense?

Anyway, the seatback and headrest wires should be easy enought to add to the plug in the existing base. I haven't messed with the headrest part in my 85 but int he 84 the backrest motor wiring is just two plugs tht fit into the main plug under the seat front. Not a big deal to remove them and put the new wires into their places.

Could the new seats have seat heaters and that is the extra prongs in the plug?

As a point of reference each motor is operated by running current through the pins opposite each other on the plug. So if you put positive on the top pin and complete the circuiot via negative on the pin just below it you will move the motor in one direction. Reverse this and the motor will go the opposite direction. You could test your seat plugs to see what controls what and find the common control input points.

The seat position memory is not a part of the seats that I know of. I think this part runs through an external control that is wired into the door switch and not the seats.

Thanks all! I found this post in a search and I think this is what I need to do to get the seat in a place where it is driveable, and then I can "fix" it when I have some time.

1stimer · #10 09-13-2009, 04:45 PM

I tried providing power to the pins as suggested in the quote from my last post, but ....NOTHING. I hooked up two alligator clips to my battery charger....red for positive and black for negative. It's a brand new charger, and I set it for 12V. What could I be doing wrong?

Sev · #11 09-14-2009, 03:49 AM

the logical and time-saving solution to your problem is to remove the seats again, and swap the slides which contain the motors, with ones off a 1st gen with the same kind of connectors which are on your car. trust me don't waste time trying to make newer seat motors (which, for a 1991, are memory), compatible with your old wiring on the car's end.

pawoSD · #12 09-14-2009, 10:39 AM

Quote:

Originally Posted by 1stimer

I tried providing power to the pins as suggested in the quote from my last post, but ....NOTHING. I hooked up two alligator clips to my battery charger....red for positive and black for negative. It's a brand new charger, and I set it for 12V. What could I be doing wrong?

A battery charger is not a power supply, you need an actual 12V supply. I used a retired computer power supply that I had laying around.

1stimer · #13 09-14-2009, 10:35 PM

Quote:

Originally Posted by pawoSD

A battery charger is not a power supply, you need an actual 12V supply. I used a retired computer power supply that I had laying around.

Thank you.....don't have a 12V power supply or a spare computer.....guess I can just run 2 long wires from the battery into the front seat then?

1stimer · #14 09-14-2009, 10:37 PM

Quote:

Originally Posted by Sev

the logical and time-saving solution to your problem is to remove the seats again, and swap the slides which contain the motors, with ones off a 1st gen with the same kind of connectors which are on your car. trust me don't waste time trying to make newer seat motors (which, for a 1991, are memory), compatible with your old wiring on the car's end.

Thank you. My question is does the seat frame stay with the currently installed seats? If it does then I will probably go this route, but the main reason for getting the new seats was due to bad seat frames causing the seat to lean badly to the left.

Sev · #15 09-15-2009, 02:21 AM

Quote:

Originally Posted by 1stimer

Thank you. My question is does the seat frame stay with the currently installed seats? If it does then I will probably go this route, but the main reason for getting the new seats was due to bad seat frames causing the seat to lean badly to the left.

usually it's the springs that cause sagging and leaning. you are in pasadena--drive to sun valley, exit lankershim off the 5fwy, there's a foreign aadlen bros u pick parts junkyard right there on the corner of penrose and telfair. they have tons of older gen w126's there. go find one with good seat slides and motors, and buy them with a warranty, and install them on your car