Author Topic: No Audio..... and a mystery connector (Read 5772 times)

dvmotorsports · « **on:** January 13, 2010, 09:16:59 PM »

So my wife's 318is is 99% working right now. Just trying to fix the audio.

Here is what is going on. Everything is factory except maybe one component.

This system has the OEM radio and 6 disc changer.... and this amp

Is that factory? I wasn't getting any sound with it hooked up. So I disconnected it, still nothing.

Could this connector be the culprit? I can't find the other end.

DesktopDave · « **Reply #1 on:** January 13, 2010, 09:22:22 PM »

No way that amp is factory. Alpine did do many of the OEM head units though, so some of their stuff works on our cars. I think they're called m-bus systems.

Did you hook the remote amp/power antenna wire up? Looks like you did. Not sure what the connector is. I don't believe that any of the M42s had the "BMW Premium" audio system with the six speakers & remote amp.

dvmotorsports · « **Reply #2 on:** January 13, 2010, 09:24:53 PM »

As far as I know, all the wires are connected except the white one in the shadows where the radio goes. It has a blue connector on it. Anyhow, it was spliced in somewhere and it didn't belong there, so I disconnected it.

I have power to everything, just no sound.

DesktopDave · « **Reply #3 on:** January 13, 2010, 09:34:40 PM »

Mostly all amps need a remote power-on signal from the head unit. There were two white wires on my old car. Remote power was smaller gauge, so was memory (12v constant, yellow wire?) or light dimmer IIRC.

One other thing I recall from doing this last time. When I wired a new unit up, it wouldn't turn on. I know it's not the same as your problem, but sounds similar. The new Blaupunkt was designed differently than the OEM unit. It was not getting enough power from the memory (12v constant) wire. I ended up tapping power from the meaty 12v+ wire on the 4-way blinker switch (hey, it was convenient) and it's been working ever since.

dvmotorsports · « **Reply #4 on:** January 13, 2010, 10:40:24 PM »

So I did some more digging and found this

The white wire I was describing earlier that was spliced in began at this filter.

I also noticed a speaker wire hanging down below the passenger knee bolster. It wasn't a factory wire.

So I am done for the night but I am thinking that there is a crossover under the dash somewhere.

Perhaps that is why there is no sound. I also found a LAN cable receiver next to where the noise filter was. Haven't been able to trace it yet, I have to take the passenger seat out and lift the carpet first.

DesktopDave · « **Reply #5 on:** January 14, 2010, 07:26:30 AM »

They used telecom cable for wiring in a car?!? CAT5 would work well for signaling voltages, but in a car's electrically noisy environment IDK if twisted-pair would filter that well.

dvmotorsports · « **Reply #6 on:** January 14, 2010, 10:56:53 AM »

Well I know in newer competition systems, and maybe general systems as well, CAT5 is used to control subwoofer gain to the amp. Maybe it's not gain, but they use it for something. But this is by no means an upgraded system.

The rear speakers are stock as is the deck. Dunno about the front's. Going to pull the cover on those today as well as chase that CAT cable.

DesktopDave · « **Reply #7 on:** January 14, 2010, 11:06:47 AM »

I've upgraded mine, but the stock wiring was all still there. Looks like you have a bit of it still in the car too..maybe edit the amp out & patch everything directly?

Makes me want to wire up my premium system...I have most of the bits but not many of the speakers...

dvmotorsports · « **Reply #8 on:** January 14, 2010, 11:18:27 AM »

Well shit, I should have found the ones from my car and threw them in the DME box. But the magnets might have caused some issues. But it's not like the DME is 100% anyway.

As for the wiring, I just want it to be stock setup. Aside from a suspension upgrade, I would like to have this car looking as stock as possible......because you can't see under the hood.....

DesktopDave · « **Reply #9 on:** January 14, 2010, 12:22:59 PM »

I might have a stereo harness if you need one. Not sure if it's the Premium or stock one, or if there is any difference.

However, it'd be a PITA to pull that through any car that had an interior...but so easy when it's stripped!

dvmotorsports · « **Reply #10 on:** January 15, 2010, 11:11:06 AM »

Well I am picking up a parts car next week. So if worse comes to worse, i'll get it from there. Agreed about it being a PITA.

superj · « **Reply #11 on:** January 18, 2010, 08:15:54 PM »

and, when you hook an amp in line on our cars, you cannot hook the grounds for the radio up or it will cause low sound issues. if you are running straight from the hu to the speakers then it will work like a normal car system. no idea why, just found it to be true on a few e30s.

dvmotorsports · « **Reply #12 on:** February 04, 2010, 04:26:10 PM »

So I got back into tearing the interior out today. This car has the OEM car phone system in it. That is what the CAT5 is for.

I also finally got a 9v and tested the speaker wires at the deck. They all buzzed. So when I plug the OEM deck back in, if I get no sound, the amp on the deck is probably toast. Amirite?

Oh and the cellular system is complete. It appears I have every piece to it except the phone. Wonder what it's worth if anything....

dvmotorsports · « **Reply #13 on:** February 04, 2010, 10:53:04 PM »

Here is the system I pulled out.....

DesktopDave · « **Reply #14 on:** February 05, 2010, 07:19:10 AM »

Yeah, you're probably right. Do you have a spare deck to toss in? I pulled mine and installed a newer Blaupunkt. The red backlight matches fairly well. The OEM BMW CDs look good too.