Radio Connector - 17 Round Pin

[SniperC4007]

Does anyone know if pin 17 was used for anything? I spliced in the 17 pin connector on my 89 535i and the plug I got from the scrapyard many years ago has a wire in socket 17. Everything I find on the pin-outs shows as 17 not being used.

I'm using the CD43 Business CD unit. I have every other wire connected and functioning (speed input for volume, illumination, i-bus interface, antenna, speakers, telephone mute)

[moroza]

What connector is this? Later cars had this:


But early cars had a bunch of smaller connectors, none of which have 17 pins according to my wiring diagram.

It may be for some obscure and now obsolete fax machine or cellphone.

More importantly, it all works anyway, yes?

[SniperC4007]

Here is a picture of the connector, the lock in tab has broken off. I wonder if PIN 17 was used for Steering Wheel Controls input?

IMG_20180619_140214.jpg

[moroza]

That's a later style plug. Pin 17 talks to the OBC. What they talk about, I don't know, but I would guess that only an OE radio has anything to say on that channel.

Update: this info is from 1990 wiring diagrams, not experience.

[zkd]

Pin 17 in e34 talks to cluster to show station name etc. On high end cluster. But not all radios use it. On e36 98 model and up it used for m-bus. The cd43 uses it as m-bus if you connect it the cluster it will start giving you false warnings.
This info is from experience.