The Mysterious Backside of a Becker (86 300E w124)

[gleep]

So my becker, being quite broken, is going to be replaced. The wire harness kit I got from crutchfield is making most of the process easy, even for a neophyte like myself. I've run into a few mysteries, however.



Above is the backside of the mysterious becker.

A) Unknown [Edit: Antenna]
B) const power/memory [12v+]
C) light? [illumination 12v+]
D) power [ignition 12v+]
E) ground
F) Unknown [Edit: Alarm wire, don't try to hook up to new head unit ]
G) Left front, left rear speaker
H) right front, right rear speaker



Here's a closeup of the plug for mystery F. The wire has a sleave on it, so I'm not sure if that's one wire with a stripe or two wires that are really, really friendly. In either case, I've no clue what's going on with that plug.



And now we have the fun stuff.

I assume B) and C) go to the front speakers, I'm not sure since if I apply a battery there's no result. (The two sets of wires not shown go to the back speakers and I got sound out of them fine from the head unit when I plugged it in for a bit; these are the sets that were plugged into G and H on the first pic). I believe that A and D have something to do with the fader. [edit: note, the black plugs and white plugs were originally connected]

What I think crutchfield's harness kit is doing, is turning the left speaker connection (G on the first pick) into left rear +/-, and right speaker connection (H) into right rear +/-, thus bypassing the fader. [Edit: Nope, the wire harness kit didn't bypass the fader switch.]

A) and F) from the first pic probably have something to do with the speed volume adjustment and power antenna, but I'm not sure which is which. [Edit: see above]

When it comes to the mystery wires on the third pic, I'd really like to know which is doing what. I'm contemplating turning the fader knob into an AUX input (my head unit has two). [Edit: still contemplating this]

Any help greatly appreciated,

--gleep

[Stoney]

Well it appears as if the F plug is a shunt to an Amp and the final set of mystery wires are the outputs to front/rear after the amp.

Prolly get a line level signal if you tested the output.

Clarion and Mitsu had a similar set up in early 80's to 90's Volvo 240/740 series but used a DIN connector into the amp.

Giveaway was finding the Y plug at the main rarness connector to tap 12V+ and Remote switch on from the antenna feed, etc.

[Hit Man X]

FIRST PIC:

A = antenna
F = factory alarm kill, don't hook it up
G & H = R/L speaker outs

BCDE = power, ground, memory, and dimmer.

Grnd = Brown
Dimmer = Grey w/ Violet tracer
Switched = Red w/ white tracer
Constant = Black w/ white tracer

Double check the switched/constant. I always transpose them.



Not sure on the fader bypass, headunit power is crap so I don't waste my time even hacking up all the wiring. I just use two channels from the HU until I get around to installing a small amplifier. 30x4 will SHOCK you in sound quality.

[gleep]

Yeah, figured out the antenna wire last night. Glad I know what F is, and it'll stay unplugged.

I currently have sound out of all the speakers, but the quality sucks (the fader switch is bad). And, well, we all know about the speaker quality to begin with. Heh.

I was contemplating getting a small amp and just running new wires for everything... now I'm sure I will. (I have new speakers on order now, just add the amp to that.) My new head unit has pre-amps for everything, may as well use them.

Now just to find the bloody screws for the ash tray I misplaced...

--gleep

[Hit Man X]

Good deal, you can get great deals on small amplifiers. Post up pics of the install if you get the chance.

[ohman]

Originally Posted by gleep

Now just to find the bloody screws for the ash tray I misplaced...

--gleep

I had the same problem too. Were you able to find that bloody screw for the ash tray, and if that screw was left in the ash tray, would it cause any problem later? Thanks!

My 1993 Mercedes 300E 2.8 doesn't seem to have the same Becker radio as yours... Is it a Becker 1432?? Can anyone identify what A and B are (see photo below)?? And for C is it still the "alarm" thing that I should not reconnect to the new head unit? Also for D, is it a fuse? Many thanks!
See picture at here

[compu_85]

You have a 1432. A is the trigger for the power antenna and the amps, C is the plug for the speed sensor and phone mute, B is for the alarm (leave unhooked).

-J