'94 R129 Audio - Wiring Info Needed

[E55BOF]

The car is a 1994 SL500. It has been fitted with a Parrot hands-free kit (and an aftermarket immobilizer, but I think that has not affected the audio wiring); all bar one of the OE Mercedes connector plugs (see Note 1 in the attachment) are gone, and the wiring is a right bugger’s muddle of bullet connectors, twisted and taped connections, inline fuses and extra wiring using (by the look of it) odd bits of wire that were handy.

I’ve managed to isolate all the wires which appear to be part of the OE loom (the one with cloth tape wound around it), which also includes the coax cable for the aerial. The table shows what I found with a multimeter.

I’m fitting a Blaupunkt Santa Cruz radio/CD head unit; no amp, no CD changer, no ‘phone, nothing, except for the head unit.

It has feeds for rear speakers, but there are none fitted to the car. I presume/hope this will not be a problem if I simply set the front/rear balance to all front?

I have identified two permanent live feeds, one thicker than the other, an earth, an ignition switched live feed, and an illumination switched live feed.

I have no idea what the rest of the wires do. What I now need to find out (and I’ve tried until my head is spinning…) is which wires feed the front speakers, and which ones signal the aerial to extend and retract. Can anyone help?

 

[RichardF]

Ok here goes

Brown (Earth)
Thin brown (boot mounted CD changer)
Red/white thick (permanent live feed from fuse C)
Brown/blue (????????) maybe parrot related
Grey/Blue (dimmed interior illumination)
Black/Green (VSS/GALA)
Black (left rear speaker negative)
Black (Right rear speaker negative)
Black/White (left rear speaker positive)
Blue (power for aerial)
Black/Green (right rear speaker positive)
Black/Blue thin (Should be switched live with ignition on 12v feed from fuse A)

The wiring diagram is for a bose setup but the colours match, I assume where it says rear speakers this is just your doors.


ETA

I put in a Kenwood unit, fortunately the ISO connectors were plug and play. I fade it all the way to the front, it sounds fine.

Good luck

 

[E55BOF]

Richard, you are an absolute star! Thank you very much. Kissy Kissy Kissy (but no tongues)...

Not just the colours match; so do the functions I already know about. Woo Hoo!; game on...

I presume the VSS/GALA is a speed data feed for a head unit which requires it? If so, I'll just tape the end and ignore it.

The brown/blue is a mystery to me, too; it does appear to be part of the OE bundle, but perhaps is not. It's such a jumble in there, it's hard to be completely certain.

I'll check the black/blue thin again; it was the last one I did, and with four different checks on each wire, resetting the multimeter after each two, I may have made a mistake.

You may be able to answer another query. I've just pulled the boot trim off to take a look at the electric aerial (genuine MB part, but not working, and I have the same type to replace it; I only found out subsequently that masts can be replaced separately).

The OE loom for the aerial has only three wires - brown, red/green, and blue. The aerial's connector, however, has four pins. Courtesy of bullet connectors, the blue wire feeds two of those pins, via a four-pin inline connector. I assume the brown is an earth, and if the blue supplies power to two terminals for the aerial motor, what might the red/green wire do?

Thank you once again

Dennis

 

[RichardF]

For the antenna, brown is earth, Red/green will be live, the blue wire just provides the raise/lower command.

Just tape up the GALA wire. The same goes for the brown/blue wire, could be the factory alarm, but I don't understand why it shows 3.7v.

If your thin black/blue wire stays live, then the radio won't switch off with the ignition. The installer of the previous radio/parrot/alarm may or may not have an answer, who knows.

 

[E55BOF]

All good (except the aerial- new thread coming). The thin blue/black is indeed switched, but I must have tested it with the key still in the ignition after switching off, so of course it was still live until the key was removed. Thank you once again.