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Install GROM Audio Bluetooth with OEM Mic

DIY: 
68K views 140 replies 33 participants last post by  t3ddftw 
#1 ·
Hey guys, this is my first post here. Just picked up a 2000 M5 last week, I'll have more on her in another thread. Just wanted to share this quick DIY with anyone installing a GROM system in the trunk of their E39. When my kit arrived I noticed how short the lead from the mic to the GROM box was, I would have need 2 extensions and to tear a bunch of interior panels out of the car. Definitely not what I wanted to do. So I figured this method out. Also, as a note, I tore my trunk apart, you can do this just opening the cover the CD changer you'll be taking out for the installation.

You'll need roughly $10 worth of stuff from Radio Shack and AutoZone, as well as maybe 30 minutes of your time. If that. This has worked for me for an hour now. I'm not responsible for you messing up your car, nor do I know if this will mess anything up over time. I just now that it works now.

Supplies:
1/8" Mini Mono Plug from Radio Shack -> Radioshack 1/8 Mini Mono Phone Plug : Phone Plugs | RadioShack.com
A pack of T Splice connectors from AutoZone (16-18 guage, I think)
2'-3' of two colors of wire

First find the wires coming from the mic into the trunk. It's 3 wires, a brown w/ white stripe, a white, and a shielded ground. They're on a white 3 pin connector. Despite the pictures, you only have to pull down the CD changer cover. I didn't know this when I started, so I pulled the whole trunk apart.



And a better picture of the connector with the wires you're looking for. You can unplug this to work on it, but ultimately it gets plugged back in since the OEM mic is powered. The brown wire with the white stripe is your negative (-) and the white wire is the positive (+)



A picture if the patch cable I put together. My wires are blue and green because that's what I had laying around. The blue is the negative and the green is the positive. when you make up the mono plug end, the longer of the two prongs is the negative.



Splice the T taps in, and hook everything up, and you're good to go. Just remeber brown w/ white stripe is negative (-) white is positive (+)



Hope this helps everyone. I'll try and update this to let everyone know how it's holding up in a week. My M5 isn't my daily but since I just bought it, I'll probably be driving it a lot.
 
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#4 ·
Thanks, figured I'd try and contribute something right out of the gate. I have really been active on automotive forums way back since I had my first car. But I think with M5 it'll be a little different.

Great post!

Tell us what you think of the BT streaming audio quality...

I just put the GROM kit with BT in our X5. I'll try to write up a little comparo to my super-on-the-cheap BT DIY.
Thank you as well. As far as bluetooth quality I'm happy with it. I think a lot of it has to do with your phone. For example, I have a Nexus 4, and for some reason Google can't bluetooth straight themselves with the phone. So I've had to apply a fix that kind of resolves the quality problem. It was really muddy sounding now, it just kind of skips everyonce in while. However, people with Samsung, HTC, Nokia, and probably any other phones don't have this problem. It seems to be a stock android problem. I had an iPhone laying around and tested it out with that and it sounded great. I think you'd be hard pressed to tell the difference between a plugged in aux connection and bluetooth.
 
#5 ·
Excellent post, and very useful. I had wondered if one couldn't use the existing wiring for this.

Still, I don't know if the microphone is installed in my car, but if not, and before I buy one, I'd like to know how well yours is working with the Grom.

Also, which wires did you tap for power/ground?
 
#6 ·
Mine is working fine. if you have a microphone in your car you'll be able to see it up my sunroof controls, there will be a small, rectangular, plastic grill. Are you asking which wires were tapped for the GROM Unit? If so, I don't remember exactly, but I know that it's in the instructions.
 
#7 ·
Thanks Frederick. The microphone is not there, but the cables are, so I've ordered one. Actually, it is the DSP adapter that needs a switched 12 volt & ground, and I realized that I am not supposed to tap anything off the DSP amp. No biggie, as I can get it off the CD changer connector. I just didn't care to snake a wire over to the other side of the car.

Have a great one!
 
#8 ·
Has anyone else got this to work? My car did not come with a mic so I bought the updated version, but I still cannot hook it up to the Grom unit. I buzzed out the connections to the front to verify the connector. I tried 4 combinations of wiring (swapping the wires and plugging / unplugging the connector) and got nothing. The passive mic that came with the grom works so it isn't the unit.

Should I see a voltage on either of those lines? If so, what?
 
#87 ·
The same question from me: has anyone actually get this to work???

I see the thread starter left the shielded cable plugged in, hence my question: what is in that shielded cable? What would one without factory phone connect it to in order for the mic to work with GROM unit?
 
#9 · (Edited)
Well I think I know what I'm missing. I traced the other side of the white 3 pin connector to a large blue connector in the CD changer area that isnt plugged into anything. I assume I a missing a box that provides power to the oem mic. Does anyone know what that box is?


Edit: I think I am missing this SES jumper

 
#11 ·
Do you guys experience a little sound distortion when your playing music from it? I get a very faint static sound if I turn it up on a quiet portion of a song/track.
 
#12 ·
This post was extremely helpful.

I had to get the DSP conversion kit. I grabbed the +/- wire connections off the DSP connector - I am not sure if this was a good call.

Before adding the DSP conversion kit I was able to switch songs via the steering wheel and stereo... now I cant and screen wont stay on the menu - it hops back to the tuner screen where GROM is displayed. Makes we wonder if I've created some sort of interference.

Otherwise the streaming quality is pretty good.
 
#14 ·
Mine is in the trunk but close to the back seat. I used to have it in the compartment where the nav is located but my signal would break up sometimes. Even with it near the rear seat if my phone is in my pocket the signal goes in and out sometimes.

I usually just keep my phone in the pocket in front of the shifter.
 
#16 · (Edited)
Moving on.

Has opened the microphone location. No free wires at all. How hard is it to run a wire from the boot / trunck to mic location. I have sunroof too. Any suggestions please?

Edit. The Grom mic wire is very short - thank you GROM!

My plan is to run to wires from the back to the overhead light. I think the OEM mic is powered, so I will have to get power from that light there, right?
 

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#17 ·
Mine still isn't working. I had the factory wiring up to the mic but mic was missing so I purchased one at the dealer. I have it wired up exactly like the original post. Any suggestions?
 
#23 ·
I bought the mic and jumper but still not working at all. I have voltage at the mic as well.
 
#25 · (Edited)
Need to remove trunk liner on left side. Zip tie mic wire to wiring loom and follow wiring loom path to back seat. With back seat removed, you will tuck the wiring behind the rubber trim that overlaps headliner working from rear seat level up and all the way around until you get to the front windshield. Then keep tucking wire until under rubber gasket until you get to the headliner plastic cover in center. Remove this and pull wire under headliner into this cavity and then you will have the mic in the correct location. I think there was a Youtube video on this that I watched. Search on youtube and watching it will be helpful. I initially mounted my mic behind the headliner grill like factory mic. But audio was muffled and I ended mounting it on the outside.

For Bluetooth dongle. I taped or zipped tied it to a vertical bar on back seat support frame before putting rear seat back in place. There are no visible wires.
 
#27 ·
Thank you! I have heard that the wire can be routed behind the rubber trim, but thought it was a myth. Now that I know that it can be done, this the route I am going to take.

Was the cable the GROM mic came with, enough? When I extended the mic cable, it ran from stop light to the mirror (at the mirror level, parallel to the ground)
 
#33 ·
it seems that you had the connector for OEm microphone, right?

and you adjusted it to fit the GROM mic?

My situation is opposite: I have the OEM mic, but no plug for it from the car. Therefore I am looking to retrofit a connection from the GROM mic cable to end into a oem bmw 3 pin plug to go straight into the oem bmw mic.

does it make any sense?
 
#36 ·
Connected my OEM mic to a Grom the other day with the help of this guide. I took the stock mic plug in the boot apart and jumpered the new lead onto the pins then reassembled rather than using taps.

All works great, however I am having some issues with bluetooth signal quality, think I need to re-position the Grom and find a better location for it.
 
#37 ·
I also used this guide to connect the OEM mic (2002 build date M5 with factory "Startac" phone option) to the GROM unit in the trunk.

I tapped into the factory mic cable in the trunk then ran my mic cable with the BT dongle cable behind the trim pieces in the trunk and under the rear seats. The rear seats come up with just a sharp tug on the base of each seat. With the BT dongle under the rear seats, the BT connection to my phone up front and the call quality are great. The factory mic works really well.
 
#38 ·
I wonder if anyone that has the GROME system with the intravee working ?
 
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