1991 318is Radio Wiring

[c0rbin9]

So the previous owner saw fit to power the aftermarket Kenwood head unit by stuffing the power wires under some random fuses in the fuse box. I'm not an engineer or anything, but I don't think that's correct, so currently I'm trying to clean up the install a little.

Here's what I've got:



As you can see, there are no power wires. The power wires have been cut:



Where are these supposed to go? He obviously cut them from somewhere, but where? There are tons of radio configurations in E30s... I'm lost.

[c0rbin9]

Did a little more research and went hunting for the wires at C302 connector. Here's what I found:



Kind of pissed.

[c0rbin9]

Is it just these wires + the speaker wires, or are there others? I'm trying to wire my head unit, in a way that restores the factory wiring if possible. It seems difficult to route the wire as factory without removing the dashboard.

[Kershaw]

You're lucky that you have the 4 twisted pairs of wires. You can wire that right in to your stereo. Each twisted pair is one corner. Once you have power to your stereo it should be easy to determine which set of wires is what.

Purple is switched and green/red is constant. Brown is ground. White is antenna power. You're going to have to hunt inside your dash for the wires, maybe get a flashlight.

[c0rbin9]

I'm pretty sure the wires you are talking about are long gone. They were cut where they connect at C302. It seems like I need a new pigtail.

[varg]

Since that little connector you posted a pic of is the part that plugs into C302 (see this for pin arrangement, see below for pinout: http://www.e30zone.net/e30zonewiki/index.php/Loom) you can just crimp splice some wires to it and run a new pigtail to the radio slot. A pain but not too terribly difficult, you're better off than if that connector was missing.

V - Fuse 21, hot at all times
W - Light switch (display dimming)
X - Fuse 12, hot in accy, run, start
Y - Ground

Z - Fuse 28, hot at all times (power antenna)

This is all from the ETM for the 318is, which I have a very complete version of, PM me and I'll e-mail it to you if you'd like.

[c0rbin9]

That would be awesome, I haven't been able to find a complete version for my car.

I thought the same thing about re-using the old connector. Thanks!

Hopefully I can run the wire nice and cleanly.

[c0rbin9]

Okay, I rewired the harness and it works!

...for about 3 seconds until the fuse (fuse 21) blows. Time to get out the multimeter... not what I was hoping for, but hey, electrical troubleshooting is kind of fun.

[c0rbin9]

Update: we've got tunes! Not sure why, but the fuse isn't blowing anymore. I replaced the 30A that was in there with the correct 7.5A and it has been working fine. Here's the wiring I had to build:





Pretty pleased with how this turned out. When I got the car, the power wires were stuffed into the fusebox and all the joints were just electrical tape. Now everything is soldered/crimped and I'm using the factory harness (more or less).