[posted this in the AMG forum as well]

I recently purchased the Grom Audio unit for my '08 SL, since I was looking for a way to listen to my iPod or cell phone through the factory Comand system. I really didn't need anything fancy, just a simple 3.5mm jack would do. It's what I did in my W203 since MB offered a $40 cable to connect to a factory connector in the passenger side kickpanel. And one of those radio frequency poor sound quality things was not an option.

I was not too thrilled to hear that any iPod-ish option was not included in the (MOST fiber optic) 05-08 R230 SL's. And that my only solutions were some units in the $450-600-800 range.

I did find the Grom Audio unit, which comes with three inputs - USB, and a couple of ports that you can (buy from them) additional cables to use bluetooth, or your iPod, or a 3.5mm jack.

$300 bucks later for their box plus another $10 for the 3.5mm cable, it's in my car.

It's a surprisingly small box. Install is relatively straight forward - they've designed the connectors and plugs to be identical to factory. The problem is that the CD Changer in my car had a different shaped connector than what came with the unit. Funny that the silver box (I'm assuming it was the car's amp, or something similar to it) next to the CDC has the right connector.

You will need to remove the panel behind the drivers side seat (where the triangle window is), which also means removing the door step and rubber, and the panel under the rear cubby, and all the screws associated with those. Overall, disassembly is more work than the actual unit itself.

Since the connectors aren't the same (damn CDC) you will need to remove the pins from your factory connector and realign them into the Grom's connector. But no splicing is required - all the pins fit perfectly. And I don't know why Mercedes puts two +12v wires into the connector and one Ground wire, so I hope/think I chose the right 12v.

Removing the CDC is pretty difficult, so I just loosened everything and stuck my hand underneath (BARELY) to remove both the power connector and fiber optic connector. Left CDC in place. If you have big bear claw man hands, you will need to recruit your children or wife to help you.

I mainly use the USB mode (with included free 2GB USB stick) to listen to music. Quality is surprisingly crystal clear. I also routed the 3.5mm mini-jack cable through the armrest, which will require you to remove the rear center cover, and do some disassembly of the center armrest (with the smallest torx bits you've ever seen). But you can make the install pretty clean if you're inventive. It will take you some time though if you want to do it cleanly. But comes out pretty good. I also found why my armrest doesn't stay up - the little gas strut tube is done for. Getting that on order tomorrow...

Overall, the install came out VERY clean, even though it took MUCH longer time than it should have due to the complexity of the R230. But the Grom unit itself is pretty simple.

Overall, USB and 3.5mm audio quality is great. On USB mode, the unit uses the CDC menu as 6 discs, in which disc 6 is the Grom firmware menu, so you really only have 5 "folder" options. Within that, the Comand system only recognizes the first 99 songs (files) of every disc. So you technically only have room for 495 songs on USB. Might be a problem for some of you with massive libraries.

Also, you can tell that while the fiber optic system sends information VERY rapidly, one of the processors (either Comand or Grom) cannot process the information as quickly. You notice this when trying to quickly skip songs, something gets hung up and you get a delay. And/or it jumps back to where it started. Or the music blips a little bit for about 20 seconds. It's not as smooth as it should be in today's ultrafast world. Also, long song titles don't scroll - you get X amount of characters and that's it. Lastly, something didn't initialize correctly last night when I started up and drove home - the unit would not recognize USB for about five minutes. It eventually came back (I guess it reset itself), but it was an odd situation.

Overall, I'd say the unit isn't perfect. But for the fact that someone made an "integrated aftermarket" solution, they did a good job. It plays my music, cleanly. And for $310 bucks, I'm satisfied. I'd be dissatisfied if I had paid double for it. And I like to listen to my iPod/etc when the radio is playing terrible music or every station in the city has decided to conspire and play commercials at the same exact time.

'65

 

i was also looking for the same thing. i was wondering if it has a bluetooth option to stream songs and pick up calls. does yours have the same function ? i know i installed one on my friends lexus and that grom model came with it. which model did u buy?

 

This is the model I bought: http://www.gromaudio.com/store/most_...pto_fiber.html

And it does say that it can do those functions, but you do need to buy the $50 accessory cable as well.

 

Having initiated a subset of problems with the installation of my GROM, I am confused by the installation of the GROM in this post at the CDC location in the trunk. Mine is behind the head unit and working well but only if I reset the power connection to it every time the car is shut off for a number of hours. I'm quite certain that both techs that worked on my install were convinced the ignition HAD TO BE A BONAFIDE 12V CONSTANT power CONNECTION (required by the GROM) but did not find a true one. In the ensuing issues after a dead battery and fuse inspections I had to spend 4 hours labor with MB to find I had pushed the connector to a fuse out of the box when replacing a fuse. It disabled my pre-safe until problem located. Cheers to MB Spokane and service mgr Tim Duff. Still hunting for a good 12v constant for the unit if anyone has one down.

 

I am about to pull the trigger on one with the blue tooth accessory.
To me it makes sense to install in back because it basically replaces the CDC.

If I understand this correctly it doesn't matter where it is in the fiber optic loop.

 

Maybe the plug was wrong in this original post because the plug swapping goes on behind the head unit where the CDC connects. No issue there as reported by techs one and two. The issue is finding a good CONSTANT 12V. Grom has pretty weak support but did suggest placement in the loop was important and if the module is back at the trunk OR in front, it's still in the same position... one end of the jumper between the CDC and head unit or the other.

 

I have horrible technical skills, especially when it comes to pulling apart the most expensive car (to me) I've ever had..... I'd be fine buying the damn thing but wish I had someone with knowledge to get it installed cleanly for me.

Stupid non iPod/bluetooth car!!!!!! Damn you! I don't even have a computer to burn CDs!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Something I've found is that if you go to the store/gas station for a quick 5-10 minutes, when you return the Grom unit is locked up (in USB mode). It takes about 10-15 minutes of driving for it to reset and play music again. Definitely an annoyance.

 

You mentioned in the original post there were two power supply wires and you picked one. Do you know if you have a constant 12 volt to the grom unit?

Sounds like you are using a switched power supply. Maybe if it were constant it would not have that issue?

Have you contacted Grom?

 

I honestly don't know. When I did my checks, I was watching the voltage with a multimeter with the car on, car off, car locked, car unlocked, radio on, radio off, etc. Both wires measured the same.

I haven't contacted Grom, I've been meaning to. Haven't had a chance to drive the SL a lot lately

 

I see no reason to tear apart the trunk to install the GROM unit but I have been unsuccessful at convincing any installer that the ignition circuit may not be live 24/7. I agree that the unit is temperamental even when operating but for ipod integration I can get by even with it's quirks. Right now in lieu of finding a constant power supply, I have a switch wired into the ground for the GROM and I reset it after being parked by flipping the switch. It resets and piddle around until I get it playing. Not what I had in mind....

WHERE IS A 12V CONSTANT IN THIS CAR?? A tech suggested the fuse box near psgr floor but I dunno?? neither does anyone else!

 

I just read the install manual. It doesn't say anything about making sure it is a continuous power supply. It instructs you to unplug the power from the CDC, check polarity and plug it in the Grom.

Viper,
Do you have the same problem when running the Grom with the 3.5 aux cable?

 

TTTodd, I honestly don't know yet, since part of the reason I got this was so I could stop carrying my Ipod between different cars - I love the USB (hard drive) option. Even though searching through folders and 495 song limit and occasional stalls is an annoyance.

 

I ask because Im thinking it could be the Comand unit.
I know when I have a DVD full of MP3s it sure takes a lot of time to switch folders. Same thing when skipping tracks, you can get way ahead of it.
If it gets too confused it goes back to where it started.

 

I haven't tried my USB connection. My goal was ipod only. As to the installation manual from GROM, it doesn't say much about anything. I got the distinct impression from my first installer that grom tech told him about the 12v constant requirement. I'm as confused as anyone on the whole deal and Grom quit talking to me a long time ago. I may send the second one back too as the first one was suggested to be defective. My experience is the GROM can't lose power or it needs a reset...

 

Maybe run a line right from the battery and give a try?

 

Yeah, next move is to search for an unfettered power source but my battery is in the trunk. I would rather not go that far unless absolutely necessary. I'm just happy to have found my fuse issue. Be careful when replacing any fuses!!
I pushed the pin receptacle right out of the box by not having it centered before pushing it down. No indication on the topside...

 

Yes, thanks for the heads up on the fuse.

I would be temped to hook it up to a 12 volt lantern battery just to see if our theory of constant power is true.

Funny that us three want to use the grom in three different ways. Viper uses USB. Luey wants Ipod and I want to stream music via bluetooth.

 

Okay I am about ready to give one of these things a try. I will make my purchase in the next couple of days.

But I have to ask. Are there any other options for streaming music via bluetooth from an android phone to the stock system? I have searched and couldn't find anything.

 

Okay I am going head first into this. The Grom MST4 is on the way. I dont know what the differance between the MST3 and 4 are beside $70.00. With all the extra cables $429.97 total, not cheap.

I am installing in back by the CDC. I got to the business end of the power supply off the CDC. Sure enough like Viper said it has two power wires.

For a test I put on two meters, one meter for each power wire. I wanted to see if the power went away in time. It did not. I have had the car locked for hours with the meters attached. Both still read 12 volts. I think its safe to say this is the 12v constant we are looking for.

 

Good, so this confirms but begs the question - why are there two power wires? I still haven't figured it out.

 

It could be that the CDC current draw requires it. Instead of one larger wire they run two small ones in parallel.

With the constant power supply then why does yours need to be re booted every time you leave it sit?

Guess we will find out when I get mine installed and see if it does the same thing.

 

It only happens if it's a five minute on/off store run. It freezes up for some reason and eventually resets itself.

 

I took a 1000 mile road trip with the GROM located behind my head unit and the extra fancy toggle switch in the glove box for reset as needed. It preformed well other than the starting up ritual. Next move is to have my indy find a better power source behind the dash somewhere. My battery being in the trunk of the long wheelbase it is not handy to route the plugins to the front of the cabin. I am keeping it beyond the return date hoping I dont regret it. My situation wouldn't be as ugly if I hadn't stupidly left the reset switch in the open position draining my battery completely... and the ensuing trouble I had with the fuse box. It cost me 400 plus to find that misplaced fuse receptacle. Hope your experience is much SMOOTHER.

 

I was chatting with a Grom tech the other day about power source options and locations.

He said this

i have heard some people hook to 12v acc instead of constant
and the problem they experience is battery drain due to the GROM shutting off and not allowing the rest of the things on the fiber optic bus to sleep properly due to GROM not continuing the sleep signal.


The Grom guys said the best place for power is the actual CDC power source.