Reversing a hackjob - RMT 200 DIY - the stereo portion of my E30 M3 restoration

[Navarone]

Yellow is constant, red is switched, blue is cut from white and jumped to red.


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[CurrusDei]

Thanks Luke! Just ordered the adapter.

On jumper wires, do you have any "best practices" on how to add a jumper wire? It looks like some of the jumps on the forum are just pieces of wire shoved down into the socket beside the pin. I want to make sure it is reliable and safe

[StereoInstaller1]

I was looking at an E30 amp today, I don't think I have pins that small.

Basically a series of 8 jumper wires that fit the plug would do it...

and the adapter you need is a Metra 40VW20

[CurrusDei]

Yeh i think I'm one of the 8 wire harness on an '89 guys. I'm on a flight to Detroit for work now, back tomorrow. Maybe I'll have some time to work on the radio then. Next Steps are:

1. Bypass Amp: Luke, do you have a link to the way to bypass the amp on the M3 without cut/crimp? If not i can just do it the normal way cutting and crimping at the back.
   
2. Disconnect blue Metra wire from White OEM Amp wire. Cap OEM white wire, Use Blue Metra wire as jump to 12v constant (red)
   
3. Hope it works
   
4. Get radio antenna adapter - any ideas here guys?
   

Thanks again for all the help. Once this is done I'm going to make a dummy proof step-by-step DIY.

[StereoInstaller1]

and to make that even more fun, BMW used "fader" harnesses with an adapter to use them as a "faderless" harness in lots of M3s and later E30s, right around 1990.

Premium amps only care about 4 positive inputs, they use chassis ground as a reference.

The earliest ones (85-88) used 5 signal wires, that being 4 positives and a single ground. Later ones used 6 wires (88-90), that being the 4 positives and 2 input grounds, then the last of them (89-92) used 8 wires, being 4 positives and 4 negatives.

I have seen the later 6 wire harness in '91's and the full "late" 8 wire harness in 89's. Can't help that part, we just have to work with what you got. Sometimes I think those fuckers did this maliciously...

I can see the scene now...."Vell, it's toosday, lets use dis harness, zose Amerikans vill never know ze difference!"

I am sure they had their reasons, I am just grateful most of that fuckery stopped after the E30.

Luke

[Navarone]

You need to jump switched 12v onto the blue wire from the metro harness, if you're not using an amp or power antenna just cut the white off and cap it. If at a later date you need to add an amp you'll pull that 5v from the pre amp output section into a mini relay like SE1 said.

I don't know why he did that, maybe he left his fader in or wasn't done wiring it up. Factory VW radio does have preamp outputs for the speakers though, so that's one reason why someone would.

[CurrusDei]

Reversing a hackjob - the stereo portion of my E30 M3 restoration

My next step is to bypass the amp - Luke is there a post with the M3 amp bypass method you referenced above?



A couple other things:



- I saw that Geno only had the top speaker wires installed (only the + lines, not the negatives) Was there a reason for this? I installed both + and -. Here's Geno's wiring.







- I installed using the guide below exactly. Any issues with how i did this?

Edit * Removed, wasnt correct







- Do I need a case ground? I dont have one now.



- Right now i have the blue power antenna cable attached to my white Amp power cable. Is this wrong? Can i remove the blue cable from the harness when i bypass the amp?

- I need to get an adapter for the radio antenna cable itself. Any recommendations?



Luke if its easier to discuss on the phone I can try to call you Monday afternoon when my work gets sane.

[Navarone]

Wow, strange. Never worked on a VW, Thanks for teaching me something new.

[StereoInstaller1]

Yes, exactly....goofy-ass VAG

[Navarone]

Ok, cool. One last thing, are there three power inputs needed? "safe", constant 12v, and switched 12v on three separate pins?

[StereoInstaller1]

Yeah this deck is silly, I can't find a pinout or anything so I'm assuming the "'safe' jumper" is just constant 12v so that it doesn't lose its radio code. Is there a "safe" pin and a switched 12v pin and a constant 12v pin?

Here's how I read what you're saying.

Switched 12v goes to blue on the metra harness. The wire colors don't match, shame on you metra, but that's where it goes.

The 5v pin is the remote "power antenna output" [sic] and goes to a relay to signal antenna or amp if he wants it.

Yes, exactly, only the pre-amp output plug has a true amp turn on, it stays live on USB, AUX, CD, etc.

[Navarone]

Yeah this deck is silly, I can't find a pinout or anything so I'm assuming the "'safe' jumper" is just constant 12v so that it doesn't lose its radio code. Is there a "safe" pin and a switched 12v pin and a constant 12v pin?

Here's how I read what you're saying.

Switched 12v goes to blue on the metra harness. The wire colors don't match, shame on you metra, but that's where it goes.

The 5v pin is the remote "power antenna output" [sic] and goes to a relay to signal antenna or amp if he wants it.

[StereoInstaller1]

BTW, since you have the later M3 harness, you could easily bypass the stock amp without cutting anything, just a series of short jumpers with the correct pins would do the trick.

[StereoInstaller1]

You shouldn't have to do any weird jumps with power, as long as switched and constant 12v are wired up correctly.

This is not correct, and this deck does NOT have any sort of "power antenna output". I went through the exact same thing on the E24 I installed one of these in, you must power that SAFE jumper.

The blue wire of the Metra harness is the classic DIN "remote" connection, but it is supposed to see a 12V signal to turn the deck on, it is part of the VW security system. Remember that this is NOT the correct harness for this deck, you would have to have a VW for that.

There is an amp turn on signal in the "pre-amp" plug (albeit without pre amp signals...bastards!) but it is 5V. It powers up when the deck is on and stays on a few seconds after the deck shuts off.

You will not need this on the M3 though, as the antenna is not powered and you should not be using the stock amp. If you decide to use an amp with this, PM me and I will show you how to connect a micro-relay from Radio Shack to safely use this feature.

I STRONGLY suggest you bypass the stock amp in this install, the beeps and volume control absolutely suck when amplified in any way, I would not recommend using this deck with any amp, aftermarket or not.

Luke

[Navarone]

You shouldn't have to do any weird jumps with power, as long as switched and constant 12v are wired up correctly. That doesn't make sense that jumping switched to the antenna will turn the deck on I think you have a short or a bad component somewhere. That previous wire job was very shitty and totally suspect. I wouldn't be surprised if there was more hackery somewhere else or something got shorted and burned up.

You need to isolate each component and test them one at a time with known working units to find the suspect part or fault. Bypass the premium amp and test the speakers without it. Do you have another stereo to test each speaker individually? I use a Lepai 2020a+ to test speakers, it's cheap if it blows and small yet powerful enough to be convenient and get good sound. Run a temporary brand new freshy fresh constant 12v and ground directly from the battery to the radio to isolate all the cars power wiring and switches. (Be safe, fuse it) Do you have a multimeter? I would test all the wires out of circuit (totally cut out the stereo) for proper voltages or ground shorts, test the white wire for voltage with the key, radio, and headlight dimmer in different positions, test to make sure each speaker is isolated from another and from ground, and have proper impedance, make sure all the wires in the harness do what they're supposed to.

The static in the bass sounds like a low 12v source voltage or current, a bad premium amp if there is one or a bad amp in the head unit. You could also try a different aux cable, or wiggle this one around and the sound might cut in and out. It could also be blown speakers which may be static, but more likely be scratchy because the voice coil is physically rubbing inside the speaker magnet.

With a low source voltage/current the unit may power up but there's not enough power to run the amp inside, some units just shutdown, some try and play and sound like shit. The white May not even be to an amp or antenna. I was looking through the Bentley manual and a few other white wires could have been used (with a bit of trouble) and one of them comes from the "headlight dimmer" which I think is high beam / low beam switch, and another goes to the illumination dimmer and turns gray/red near the steering column then to the stereo.