W126 Memory seats - Page 2 - PeachParts Mercedes-Benz Forum

LandYaghtLover · #1 09-21-2010, 12:21 AM

Thanks. I will look into the relay for sure. Not sure what else it could be anyway!

LandYaghtLover · #2 09-25-2010, 02:55 PM

Pulled relay, nothing. Wonder if the relay is bad.

LandYaghtLover · #3 10-24-2010, 10:12 PM

Ok. Does anybody know the location of the memory seat module? That is, is it separate from the seat computer? I ask because I found out a few things. One was a tip:

"-W126 fuse for trunk light and memory seats keeps blowing: the wiring harness near the trunk hinge flexes all the time, and the wires have shorted. Pull the wires and electrical tape them, and you'll be fine."

Why would the memory seats be dependent on trunk wiring? So i looked and found nothing in particular. But I did find a wiring harness along the body line that was taped to the antenna. When I removed it and pulled it apart I found four wires. Two were red with white stripe. Twisted together. Upon separation, trunk light went out. The other was a brown ground (cut and unattached) and the last was a light blue going nowhere.

But I am not sure where they would even go in the first place except to a module or plug. Especially odd is the trunk light. Why run a harness down then back up to the back of the seat then again to the trunk. And its a factory wrapped harness. So clearly there is a reason this is where it is. But no module, no connector and no clue whats up with the blue wire. Got no voltage off of it. Note: Stereo system was hacked to high heaven. Antenna wires were also wrapped up in this. They may have used this harness end for antenna power. Pic of hacked wire harness:

And then I also found this long ago. I am pretty sure that only one is in the car on the drivers side. Given that the harness seems to hide under the heat vent, I am not sure of there is an open harness on the passenger side. At one time that seat was disconnect and when I hooked it up in went into a loop. So it had issues which I sorta fixed (hooked up and works). But they may have removed this box to try to make the seat stop looping. Anyway, I took it off and apart. It has the same relays used in the seat control boxes. And everything is doubled up in pairs, so it may be the controller and it may control both seats. I am going to re-solder the board tonight and see if it helps. But it sure looks ok, no burnt stuff. Pics:

I guess at this point I am more curious about the blue wire and where it may have gone.

Billybob · #4 10-24-2010, 10:27 PM

The hacked wiring loom in the trunk is the original antenna wiring, blue is the antenna signal, the reds are power, and the brown ground.

The other box your hacking is the seat heater relay!

The memory seat controller has two parts, the larger box attached to the driver's seat motor frame and a smaller similar box under the passenger seat.

LandYaghtLover · #5 10-24-2010, 11:57 PM

Quote:

Originally Posted by Billybob

The hacked wiring loom in the trunk is the original antenna wiring, blue is the antenna signal, the reds are power, and the brown ground.

Wait, how could blue be signal when there is an actual antenna wire screwed into the antenna and then terminating at the amp/brain? And I see no blue wire on the antenna. Just a black, red, white.

Billybob · #6 10-25-2010, 12:58 AM

Quote:

Originally Posted by LandYaghtLover

Wait, how could blue be signal when there is an actual antenna wire screwed into the antenna and then terminating at the amp/brain? And I see no blue wire on the antenna. Just a black, red, white.

The antenna gets 12v power from the red wires, the blue wire is an antenna UP/DOWN signal wire from the head unit through the dash switch and back to the antenna. The blue wire tells the antenna circuitry to rise/retract/ partially or fully. The radio frequency signal is a larger coaxial cable which attaches directly to the connector which exits the antena staulk at an angle.

LandYaghtLover · #7 10-25-2010, 01:03 AM

Quote:

Originally Posted by Billybob

The antenna gets 12v power from the red wires, the blue wire is an antenna UP/DOWN signal wire from the head unit through the dash switch and back to the antenna. The blue wire tells the antenna circuitry to rise/retract/ partially or fully. The radio frequency signal is a larger coaxial cable which attaches directly to the connector which exits the antena staulk at an angle.

Ok. So I am guessing there was, at one time, a connector which they, for whatever reason, removed and spiced some stuff together. Hence the lack of a blue wire on the antenna, it was probably the white one on the antenna that would have coupled with the blue.

Good to know actually since I have no radio at all right now due to the hack job. Thanks much!

LandYaghtLover · #8 10-24-2010, 10:26 PM

Yellow box appears to be for the heated seats. Crap.

LandYaghtLover · #9 10-24-2010, 10:30 PM

So, as I first thought long ago, the memory seating functionality is built into the same controllers that operate the seats? Makes me wonder even more as to why the memory seats dont work on both. One I can understand, but both with the rest of the functions being fine? Sorta odd. Then again I cant even get my vanity mirror lights to work, so I guess nothing can be too odd with this car.

Billybob · #10 10-24-2010, 10:34 PM

Quote:

Originally Posted by LandYaghtLover

So, as I first thought long ago, the memory seating functionality is built into the same controllers that operate the seats? Makes me wonder even more as to why the memory seats dont work on both. One I can understand, but both with the rest of the functions being fine? Sorta odd. Then again I cant even get my vanity mirror lights to work, so I guess nothing can be too odd with this car.

The memory function will not work if either of the controllers is faulty.

LandYaghtLover · #11 10-24-2010, 11:51 PM

Quote:

Originally Posted by Billybob

The memory function will not work if either of the controllers is faulty.

As I said, they both work fine now unless there is something more wrong with them. Possible given that at one time they did not.

@ Cherry - Fuses look ok, but I thought the rear upper light only comes on when the back doors are open. I thought the lighting circuits are separate, as I was told. Although I swear when i first got the car the back did light up. As for anti-theft, that module is missing. Taken out, I presume, by the wonderful stereo installers of the pervious owner.

Billybob · #12 10-25-2010, 12:51 AM

Quote:

Originally Posted by LandYaghtLover

As I said, they both work fine now unless there is something more wrong with them. Possible given that at one time they did not.

@ Cherry - Fuses look ok, but I thought the rear upper light only comes on when the back doors are open. I thought the lighting circuits are separate, as I was told. Although I swear when i first got the car the back did light up. As for anti-theft, that module is missing. Taken out, I presume, by the wonderful stereo installers of the pervious owner.

From reading your posts it seemed that the memory functionality of store seat/steering wheel positions and then recalling and implementing those stored position was inoperative, perhaps I've mis-read the saga! If either memory controller is faulty the ability to store, recall, and reposition the seats and wheel is usually impaired. If your memory functionality is operative then most likely you have an intermittent problem and often times that is a wiring or grounding issue.

LandYaghtLover · #13 10-25-2010, 12:57 AM

Quote:

Originally Posted by Billybob

From reading your posts it seemed that the memory functionality of store seat/steering wheel positions and then recalling and implementing those stored position was inoperative, perhaps I've mis-read the saga! If either memory controller is faulty the ability to store, recall, and reposition the seats and wheel is usually impaired. If your memory functionality is operative then most likely you have an intermittent problem and often times that is a wiring or grounding issue.

If they worked I would have not started this thread!

But they way I read your original response was that if the seats did not function correctly (manually operate controls) then the memory would probably not work either. And thats the conundrum. Both seats operate fine with controls, but both lack memory functions. So I can adjust them all I like, I just can not get either to program to memory. Which, if its all one unit, is rather odd. Even more odd that both would fail since both seats are independent of each other.

Make sense and do you see why I am so confused on getting this repaired? If I has spares I could swap the controllers out. But I don't.

If they are indeed shot and no one has any more ideas, then I will have to go on the hunt and spend some cash on replacement controllers. Which is fine. I just prefer to exhaust all possible solutions for repair before replacement.

cherry_560SEL · #14 10-25-2010, 12:59 AM

Quote:

Originally Posted by LandYaghtLover

As I said, they both work fine now unless there is something more wrong with them. Possible given that at one time they did not.

@ Cherry - Fuses look ok, but I thought the rear upper light only comes on when the back doors are open. I thought the lighting circuits are separate, as I was told. Although I swear when i first got the car the back did light up. As for anti-theft, that module is missing. Taken out, I presume, by the wonderful stereo installers of the pervious owner.

Mine have always come on when I open the front or back doors.