Adapting early E34 wiring to CD43

[TGreene]

Good afternoon guys,

I have a CD43 that I'd like to install into my 05/90 build date E34. I don't want to cut into the existing harness. I want to make a harness that will connect to the early E34 audio wiring and adapt to the CD43 headunit. I am not an audiophile - I just want a decent radio and the ability to use the car to verify that other older radios/CD changers work if I want.

Has anyone done this before? Getting my hands on the CD43 harness side will be easy, but not sure where to start looking for the side of the harness that would connect to the existing wires in the early E34. I also understand that the early E34 systems are common ground, and are a bit different than the later Hi-Fi systems.

For reference, I have the early E34 wires shown at the bottom of the following page:

http://www.bmwe34.net/E34main/Upgrade/Stereo_radio.htm

[Singing6]

I cannot speak to how the audio side of things will work on such an old E34, but I CAN speak on the trunk CD changers. For starters, the CD43 is an I-bus headunit. the E34 is serial. You cannot keep pin 7 from the E34 loom plugged into the CD43, as it will cause clash errors on the serial bus due to the different protocols. The CD43 will also require a matching I-bus trunk CD player. That means the cable and changer from a +1996 car, likely an E36.

[TGreene]

I cannot speak to how the audio side of things will work on such an old E34, but I CAN speak on the trunk CD changers. For starters, the CD43 is an I-bus headunit. the E34 is serial. You cannot keep pin 7 from the E34 loom plugged into the CD43, as it will cause clash errors on the serial bus due to the different protocols. The CD43 will also require a matching I-bus trunk CD player. That means the cable and changer from a +1996 car, likely an E36.

Thanks for the response. I don't plan on using the CD changer, I would just be interested in leaving the wiring intact so that I would be able to use it in the future to test components.

[theBMWbeast]

I’ve got a complete new hifi wiring harness, the locking arm for the radio side is broken but elsewise plugs in. Also have a hifi amp I can throw in. It’s the entire harness from trunk to head unit. $40 + shipping. I wired up my ‘89 to an aftermarket head unit instead.

[TGreene]

I’ve got a complete new hifi wiring harness, the locking arm for the radio side is broken but elsewise plugs in. Also have a hifi amp I can throw in. It’s the entire harness from trunk to head unit. $40 + shipping. I wired up my ‘89 to an aftermarket head unit instead.

Thanks but I have these parts, I just want to try and retain my ability to test/use early radios.

[theBMWbeast]

The early system is completely different, as you already know. Hopefully someone more knowledgeable will chime in. If you already have the complete wiring I would personally just run that

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[ross1]

As I understand it you want to retain the ability to plug in a standard radio.
Some of the connectors might be tough to source, like the DIN loudspeaker female connectors.
What about removing the bits from a dead early radio?

[student2018]

Maybe you should try this one
https://www.germanaudiotech.com/coll...12649457221745

I did the opposite. I converted 17 pin harness to pre-1992 stereo harness with separate plugs for speakers, +12, GND, IGN and illumination to connect the OEM stereo.

[theBMWbeast]

There’s the ticket right there. I can recommend that site, used it for an adapter for my conti unit for rca outputs. Works great and everything is done well!

[Neel]

I have the rover cd-43 in my car. I ended up using a metra harness, and had to basically splice audio wires into the harness. My install is definitely not conventional as my car did not have the original amp. P/O had put a sub and amp in the car, which caused a lot of problems. I had to re-wire the car, oh and You do not need a trunk CD player for it to work as I do not have the additional CD cassette.

[TGreene]

Maybe you should try this one
https://www.germanaudiotech.com/coll...12649457221745

I did the opposite. I converted 17 pin harness to pre-1992 stereo harness with separate plugs for speakers, +12, GND, IGN and illumination to connect the OEM stereo.

Woah, nice. I spent a few hours searching before making this post and never saw that. Nice - thanks.

[markostam]

I cannot speak to how the audio side of things will work on such an old E34, but I CAN speak on the trunk CD changers. For starters, the CD43 is an I-bus headunit. the E34 is serial. You cannot keep pin 7 from the E34 loom plugged into the CD43, as it will cause clash errors on the serial bus due to the different protocols. The CD43 will also require a matching I-bus trunk CD player. That means the cable and changer from a +1996 car, likely an E36.

Not to thread hijack but THANK YOU SO MUCH FOR THIS POST. I have been running around in circles debugging the ESD Regelt error on my E34 Msport and looks like pin 7 on the C43 was the culprit. Next time you're in Boston I owe you a beer.

[Singing6]

Not to thread hijack but THANK YOU SO MUCH FOR THIS POST. I have been running around in circles debugging the ESD Regelt error on my E34 Msport and looks like pin 7 on the C43 was the culprit. Next time you're in Boston I owe you a beer.

Yea, I went through the same experience myself. Redid every single resistor and capacitor in 3 different ccm before I started doing idiot checks and noticed that the errors started when I put the C43 in. On an aside, turns out the C43 is not actually I-bus like most stuff will tell you. Its actually Alpine M-bus. But its protocol is really close to I-bus so it will work deceptively well….. until there are commands passed on the bus that dont match. Its more akin to vastly different accents of the same language rather than two different languages. This is why products like the GROM Unit that spoof the trunk CD player to give you bluetooth input say that they don’t support the C43. However, I have had a fair bit of luck with it. Probably because the trunk CD changer is the same for both the C43 and the CD43? Who knows.

As for the beers, come to “The Vintage 2022” and give me the beer there! Its basically what that event is for. (www.atthevintage.com)


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[markostam]

Yea, I went through the same experience myself. Redid every single resistor and capacitor in 3 different ccm before I started doing idiot checks and noticed that the errors started when I put the C43 in. On an aside, turns out the C43 is not actually I-bus like most stuff will tell you. Its actually Alpine M-bus. But its protocol is really close to I-bus so it will work deceptively well….. until there are commands passed on the bus that dont match. Its more akin to vastly different accents of the same language rather than two different languages. This is why products like the GROM Unit that spoof the trunk CD player to give you bluetooth input say that they don’t support the C43. However, I have had a fair bit of luck with it. Probably because the trunk CD changer is the same for both the C43 and the CD43? Who knows.

As for the beers, come to “The Vintage 2022” and give me the beer there! Its basically what that event is for. (www.atthevintage.com)


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It’s a really tricky one. I’m not going to be able to make this year's vintage but I’ve been wanting to get down to Asheville for some time now, hear it’s a really cool town. Maybe I’ll catch you there next time around!