Remove Power Seats; with no Power? - PeachParts Mercedes-Benz Forum

outofspec · #1 01-27-2008, 08:39 PM

OK I’m a neophyte when it comes to electricity. I couldn’t read a wiring schematic if I had one, and how anything electrical really works is a mystery to me. I am an aggressive hobbyist however and I try to do most of my own automotive work.
With that said, I need some help. I have a 1990 300E that I am parting out and using the engine for my 1989 300SEL with a bad cam. She is REALLY torn apart. All the electrical components under the hood, fuse box, relays, everything is out; heck, the engine is out. The front seats are in great condition and I wanted to save them before sending the remainder of the car to the wrecker, BUT … they aren’t in a position where I can remove all the bolts. It was really an idiotic move on my part but I did it. The seats worked great before I disabled them and the wiring harness is all there. I also have both seat switches. My question is; is there a way to manually move the seats, or better yet is there a way to probe the seat switch harness with a 12 volt power source to get them to move? Any help would be appreciated. It would be a horrible shame to send these seats to a crusher.
Thanks for you help.

mpolli · #2 01-28-2008, 08:22 PM

Easiest way is hook up the wiring to it.

Other way is apply power to the connector as you mention. You will need a schematic. Should not be too hard to read for that.

outofspec · #3 01-28-2008, 10:14 PM

Quote:

Originally Posted by mpolli

Easiest way is hook up the wiring to it.

Other way is apply power to the connector as you mention. You will need a schematic. Should not be too hard to read for that.

Hi Mpolli,
Thanks for trying to help me out. I’m afraid hooking the electrical system back up the way it was would be impossible at this point. I wish I did understand wiring schematics because I’ve looked at it, but I just don’t understand it. I’m afraid of frying something out if I hook up incorrectly. I have wires running to the switch terminals. As well as wires running from the firewall to what appears to be under the seat. But I can’t see underneath to be sure.

mpolli · #4 01-29-2008, 02:38 AM

If you can post a picture of the schematic maybe someone can give you some ideas. Generally there are 2 wires for each motor in the seat. They are color coded. You hook up + and - and the motor goes one way or the other. Reverse the wires and it goes the other way. These days with CAN it can get more complicated but in the old days that was it. The switches can be complicated but the wires to the seat SHOULD be straight forward. However I have never seen the schematic.

outofspec · #5 01-29-2008, 08:50 AM

Thank you Mpolli and another member who has sent me some additional information. I've got a plan together and I'll be working on the seats in the next day or two. I'll post the results on the thread.
Thanks again for the help.

raymond~ · #6 01-29-2008, 08:17 PM

in case this helps any

bhatt · #7 01-30-2008, 12:36 PM

If the switches and seats are still in the car, I don't see why you can't hook up a battery temporarily (just to move the seats).

Easiest way is to just hook up an old battery (or jumper pack) to the positive and negative battery cables in the car. Then operate the seats enough to get them out.

If that doesn't work, look at the wiring diagrams and see which wire supplies +12V to the power seat switch and cut/connect that wire (plus a ground) to a battery.

mpolli · #8 01-30-2008, 08:44 PM

Quote:

Originally Posted by raymond~

in case this helps any

Only problem is the seats are not on that drawing!

raymond~ · #9 01-31-2008, 10:51 AM

Quote:

Only problem is the seats are not on that drawing!

the coding should suffice...but since it's free, it's your turn to go to your local
library and get the info off their computer (Alldata and Chiltons).

mpolli · #10 01-31-2008, 03:59 PM

I just didn't want Mr outofspec to feel bad if he couldn't understand that drawing since I believe what he needs is what color wires are connected to what motors in the seat, and none of that is included in that diagram.

outofspec · #11 01-31-2008, 04:22 PM

Gentlemen,
You guys are truly the greatest. The spirit of this board is to help each other, and you guys have proven to be; giving of your time, responsive, and knowledgeable. I appreciate all the information, even bits and pieces, because its all a part of this puzzle for me.
Mpolli, you were the first to chime in and I appreciate the thoughts, and I can see that you got my back so thanks. Raymond, the schematic was great, I didn’t have it, and it helped greatly with my basic understanding of the problem at hand and the wiring in general. Bhatt, I wish I could hook up the battery again, but the engine is gone, all relays, fuses, etc. Bhatt, you did hit on a solution that was echoed by another member that I got a message from, to get to the source of the 12V power for the seats, and jump directly with a battery and a ground to the chassis. I have been told that there is a connector under the dead pedal (foot rest) on the driver’s side of the car that I can apply the 12V to and hopefully move the seats with the switch. I just can’t seem to get the time to get out to the garage to get it done. I am going to try it again tonight. I’ll let you guys know.
Thanks Again!

platt-deutsch · #12 01-31-2008, 07:23 PM

If you can get to the 2 wires from the motor you should be able to run 12 volts directly to it. If it runs the wrong direction just reverse the polarity of the wires.

raymond~ · #13 01-31-2008, 08:54 PM

Quote:

Originally Posted by mpolli

I just didn't want Mr outofspec to feel bad if he couldn't understand that drawing since I believe what he needs is what color wires are connected to what motors in the seat, and none of that is included in that diagram.

sorry i reread my post and it sounded testy. library was closing and i only
had limited access to the service. i really was trying to highlight the great
service of these two databases and wanting you to know. sorry...it came
out wrong. if i have time over the weekend, i can try again and search for
the proper diagram

outofspec · #14 01-31-2008, 11:14 PM

I first applied 12V at the harness connection under the dead pedal in the driver’s side foot well with a ground to the chassis. I made good connections but the switch didn’t move the seat. I tried the same thing at a connector on the passenger side, with no movement as well. I then went to plan B, which was suggested by you guys, to go directly to the seat motors. It was a tight squeeze, but I was able to get my paw under the seat from behind and remove the springs holding the carpet cover that is over the seat mechanism at the seats front. As I was able to remove the front seat bolts with the seat in it’s current position, I was able to push the seat up with the back bolts still in just enough to see the electrical connectors. Removing the larger of the two connectors revealed the male portion of an 8 pin connector. I scavenged an 8 pin female connector with long enough leads to allow me to apply 12V positive and negative to various pins. Once I found the leads that raised the rear of the seat up I was able to access the bolts. I really didn’t think I’d be able to get my hands in there but there was just enough room. I appreciate everyone who helped me get my arms around this challenge. It seems that whenever I have an electrical problem, the more I think about it the dumber I get.

raymond~ · #15 02-01-2008, 01:31 PM

for future queries which might need this...