MyE28.com

My 1988 535i had an aftermarket head unit that butchered the factory wiring harness. I am in the process of re-installing the factory cassette stereo. I am 50% there.

Can someone please just show me the backside of their OEM head unit so I can rewire correctly and get rid of the nest of aftermarket wires.

there’s no obvious clear wiring diagram. Please correct me.

Aside from the hacks that butcher things, professional and amateur alike, you may be running into problems with the factory fader and the amp in back if you have one. IMO the wiring diagram is pretty clear, but no telling what has been done in the past. In case you don't have the diagram, it's here, http://wedophones.com/BMWManualsLead.htm

Timely post, every time I step on the brake pedal my stereo shuts down The aftermarket head unit power lead is plugged into a white right angle female flag connector in the dash. I'll bet it's part of the brake circuit and when the brake lights go on it pulls the head unit voltage to its minimum.

Never fails to amaze me how badly radio installs are hacked. Seems like everything I've owned that didn't come to me with the stock radio installed had wires run all over and power tapped into places that made no sense or caused goofy problems.

gadget73 wrote: Apr 30, 2024 3:30 PM Never fails to amaze me how badly radio installs are hacked. Seems like everything I've owned that didn't come to me with the stock radio installed had wires run all over and power tapped into places that made no sense or caused goofy problems.

Yeah, that's why I would rather just see a picture of how the harness/wires looks going into an Alpine CM5907 (factory) head unit. My brain hurts going through the ETM / Diagrams, and I don't even think the stereo they are referring to is the same as mine. This is the head unit I have, I've noticed some of these have a different looking backside with the same looking face.

https://www.ebay.com/itm/186295885333?c ... gI2gPD_BwE


I will venmo /zelle someone $20 to send me a dozen photos of the wiring going into their factory cassette stereo, the same one linked above.

I can't even find a picture of the connections on the CM.
But there are 10 pages of Stereo Wiring results here on my and it includes this link
https://www.mye28.com/viewtopic.php?t=149428
Shows the left and right speakers as the yellow and blue, the power connector and some other connections all fairly easily determined as to use based on the original colors and wires that will be in the ETM

The original wiring is in my ride but it is a pre-premium ride and I got no idea what was added in the radio area. When I installed the new rig, it got all new wiring. With a non-code radio, maybe the connections were different but I recognize those speaker connections.

http://www.bimmerboard.com/members/vtbi ... stereo.htm no idea if this helps but it is wiring

I have an '88 535. Here is my factory wiring. Should be pretty straight forward.

https://share.icloud.com/photos/0b8uIBo ... gGzLOF69iw

$20 to whoever sends me this...

Im not sure if this helps, but here are photos from an OEM BMW period correct radio. This wasn't in the car when I bought it, but maybe it will help:

The unit is a CD-43 and used an "ISO" connector for power and signal.

https://share.icloud.com/photos/0d9mQO9 ... A1c5Pjx1UA

https://share.icloud.com/photos/064aO4g ... Qf_jZRHs4g

https://share.icloud.com/photos/0f8H1da ... 67h0xTcAKQ

https://share.icloud.com/photos/01bklMy ... M6uIkYT-cA


But the factory wiring behind my dash is....a nightmare.

Update on the mysterious brake pedal radio power problem. So few days ago the tach and radio were both dead. So started testing fuse continuity in-place and found #2 (row one outboard, 8A) for the Hazard Lights to be bad. Hmm, my radio is wired incorrectly ! Replaced the fuse and cleaned up the contacts and haven't had the radio cutout since. But according to the fuse cover the tach is fuse #1. Weird, need to do some more testing, but for sure the radio is not wires to fuse #13