Power Seat Pinout Diagrams Needed w126 - PeachParts Mercedes-Benz Forum

mechanicalman · #1 03-31-2010, 01:40 AM

Hey guys. I got a pair of matching grey w126 power leather seats from a 1991 300se to replace the shoddy ones in my 1983 300sd. I knew there'd be some complications with the new seats having a few additional features (headrest, memory settings, etc.) and I was hoping someone could shoot me the pinout diagrams for the later model seats so I could splice the harness to the simple 8-pin connector my old seats had.

And if anyone else with experience swapping newer power seats into an older w126 chimed in, I'd definitely appreciate it.

LUVMBDiesels · #2 03-31-2010, 07:29 AM

These are from my 1986 SDL. It should be the same...

compu_85 · #3 03-31-2010, 08:34 AM

The memory controller is different for 91, but I think the seat motors / wiring is the same.

-Jason

bgkast · #4 03-31-2010, 12:15 PM

I swapped a newer w126 seat into my SD. I don't have pin outs, but the wiring was different. I used jumper cables on the new and old seat to figure out which pins did what and swapped the plug from old seat onto the newer one. I pulled the head rest wiring up onto the seat back and zip tied it out of the way.

vstech · #5 03-31-2010, 04:21 PM

hmmm I'm thinking about taking the 93 300D 2.5 seats and putting them in my SD...
any takers on help with them?

mechanicalman · #6 04-01-2010, 11:27 PM

Thanks guys! I ended up bypassing the controller box under the seat and wiring my switches directly to the seat motors. It was actually really straight forward. I was able to use my wiring harness and just match colors for the motors. the odd pair was pink and pink/grn for the headrest motor, which i just left out. I took lots of pictures and will probably post a w126 seat swap DIY later on.

Lovin' the new leather and fresh bouncy seat springs

thayer · #7 12-05-2010, 04:43 PM

WOO HOO! picked up a complete leather interior from a 90' sel. Getting ready to do the same swap.

Oh the front seat....its feels SO good. And my kids now have HEADRESTS.

Heated seats..WHAT

joy. As roy once said....Miles of Smiles.

compu_85 · #8 12-05-2010, 04:48 PM

Cool!

Let me know how the heated seat wiring goes. I want to retrofit that into my car someday.

-J

Billybob · #9 12-05-2010, 09:33 PM

Quote:

Originally Posted by compu_85

Cool!

Let me know how the heated seat wiring goes. I want to retrofit that into my car someday.

-J

It's a completely separate system, the wiring loom has connections under each seat for both heaters, connections for a relay for each seat, connections for the switches in the center console (best bet is to get the center console from the donor car if at all possible), and the wiring loom ultimately connects to the 5-pole power distribution connector on the driver's side firewall.

mechanicalman · #10 12-23-2010, 07:14 AM

Hey guys here are some pics of the swap. You can tell where I removed the memory module/control computer from the new seats and kept the pigtails for the motors in place. The following picture show where I removed the pigtail from the original seat and the spliced it directly to the wires of the motors on the new seats with taps and male quick connects. The colors matched up exactly but sadly I have no provision for adjusting the head rest with this set up.

mechanicalman · #11 12-23-2010, 07:15 AM

more pix

thayer · #12 12-23-2010, 09:53 PM

OK, so I pulled the entire heated seat harness (power - two relays, 4 plugs, two switches, and the coin tray)...I'm not entirely certain that my seats have the heating elements in them.

I did fine one extra plug that I hope goes to the heating element, which would mean that both elements are powered by one plug on the 90. On the 88 that I extracted the heating wiring harness from, the seats had two plugs...one for the back element and one for the butt element.

Anybody know that much about the differences between the 88 and the 90? I wouldn't think that they would be that different between the two years....but I hope they are so that I didn't do all that extraction work for nothing.

RaySha · #13 03-23-2017, 10:31 PM

Hello
I am in the process of a swap of 1990 300se power seats in to a 1984 300sd. I also have the door controller and the wiring for the newer seats.
Questions:

1. Is it possible just to switch out the wiring going the seats as well as their door controller keeping only the existing 12volt power lines to make the headrest work as well.

2. Do the motors get their power through the controller on the door or do I need to connect power to each connector inside the door at the controller

Thanks