Rewiring 1991 W126 for new head unit - PeachParts Mercedes-Benz Forum

stephenson · #1 12-30-2002, 10:02 PM

I was doing OK with the stock system in my 1991 350 SDL ... OK, sure the radio did not lock on well and, yeah, one of the amps was intermittent, and I had forgotten the cassette (remember those?) doesn't work .... but, I was OK with it .... until I helped my 18 year old son install the Blau Tokyo "Santa Crutchfield" delivered for Christmas ...

Not only was the radio way cool (I know it is old tech ... discontinued actually, and Crutch sold out very quickly), but the installation, including bypassing the factory amp to use the integrated system's amp was a real snap with the included wiring harness and instructions.

Now, I am considering, again, options for my car ... I had given up a simple replacement of anything due to the dual amps, etc. I have about decided the best thing to do is to replace the head unit and rewire.

I can stumble through, but would really appreciate some pointers from those of you that may have done a rewire on this model ... mine has 10 speakers total, a couple of sets of them are bass-tweeter combos, I think. Special tools needed? Best option for the wire? (was gonna use 18 gauge zip cord (lamp cord) since is low tech and my needs are limited).

If I do the rewire, I had been looking at the Blau Santa Fe or San Diego ... anyone have better low end suggestion? No need for MP3 capability, just CD and radio. I don't want wild graphics and aluminum look ... want to match tone of the interior and original look.

Muchos thanks.

96C220 · #2 01-04-2003, 11:41 PM

I just did this in my 1989 420 sel not long ago. What You need to do is run 4 new speaker wires from behind the rear seat to the dash behind the radio. All 4 speaker lines are accesible behind the rear seat.
This completely elimiates the factory amplifers (which are inferior in comparison to the amplification in a modern deck), as well as elimitates the fader in the center console which is known to be troublesome, and gives the deck full front / rear fadability.

The factory speakers will work fine with the new deck, and actually sound pretty good, you will be pleasantly suprised.

If you need more help, or want to know specific wiring locations, procedures, colors etc...

Feel free to e-mail me

george - george@parts4sale.com

worldcom11 · #3 02-19-2003, 01:32 AM

Hi George,

I think I will eventually end up doing what you just did...rewire. But for now I can't even remove my rear seats (power seats) on the 1990 560 sel! Is the rear seat held down by those two 10mm bolts at the bottom or am I missing other bolts? Any help would be appreciated.

Andy

96C220 · #4 02-19-2003, 07:42 AM

My 420 sel did not have the power rear seat option, so I really dont have experience removing that seat. Let me know the model year of your car and i'll take a look on the CD and tell you what I can come up with.....

Stereo wiring should be the same.

Gotta Run to work now.

Take care,

George

#5 02-22-2003, 03:00 PM

Yep those two 10mm bolts and some sticky double sided adhesive is all that holds the rear bench in place. Pull up hard at the front edge and it will come away.

Definitely worth rewiring, bypassing the amps and using the head unit only. That will make a big noticable difference in sound even with the stock speakers.

Matt.

96C220 · #6 02-23-2003, 10:18 AM

One on each side - Left and right, and one in the center that may be hard to see. It is located behind the plastic piece that is designed to keep tension on the center seat belt buckles. Pull the buckles down, and you will see a black plastic piece clipped to the two metal arms of the buckles. It just clips off and the center bolt will be behind that.

Once all three of those bolts are removed, pull straight up till the seat back is about 2 inches over the rear deck, and all the clips should be free and the seat should come right out, its not heavy, but cumbersome because of its size, so you may want to be careful not to scratch the leather as you remove it.

Hope this helps

George

#7 02-23-2003, 01:16 PM

That is for the seat back, I was referring to the seat bench which must be removed first before the seat back can be taken out.

There isn't any double sided tape on the seat back either, only on the bench.

As George said, be careful removing the seat as it's very easy to tear the leather, don't ask me how I know :-(

Matt.

96C220 · #8 02-23-2003, 10:57 PM

All that held the rear seat back down was the two red metal clips that you push forward, and the front part of the rear seat pops up, and then the bench slides forwards.
I've never seen bolts or double sided tape on the bottom part of the bench....Chances are it was a previous owners handiwork.

I've seen a couple people over the years maul the metal clips and not be able to make the seat snap back.... If you dont have it pushed in ALL the way, and you apply a lot of downward pressure, you will bend the clip.

Take care,
George

#9 02-26-2003, 03:56 AM

You obviously haven't had a Mercedes with an electric rear seat. The 126 electric rear seat mounts exactly like I describe from the factory.

The seat back is mounted on two verticle rails that move horizontly outwards at the bottom when you move the seat forward.

These rails are connected to two more rails under the seat base. The motor pulls the seat base frame forwards or backwards which drags the seat back along with it.

As the base moves forward the back reclines. Nice, turn on the seat heaters and you are away.

Matt.