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Aftermarket headunit install with Bose for klutzes...
By a klutz. I decided I wanted in-dash CD for me and iPhone/USB for wife and kids. Purchased from Crutchfield Kenwood KDC-BT558U which also comes with Bluetooth for phone! Cool.
Being uniquely unqualified for such a task (big, clumsy hands, bad eyesight, no aptitude or experience, and without patience), I decided that it was a waste to spend $100 paying someone to do the work that I could spend countless hours researching here and on benzworld how to do and then waste more time screwing it up myself!
Long and short, got the thing all the way into the car. No power. Turns out I need to get power from the cigarette lighter (so I will try to connect the dimmer as well).
My question is : The microphone for the Bluetooth phone is of course a wire. I did just run it alongside the headunit so it just exited the dash rather unfetchingly from alongside the headunit. As I now am in the process of removing the empty tray and cigarette lighter, does anyone know if there is a better exit point for the microphone? Thanks.
I have created a gallery of my exploits if anyone wants a good laugh.
I have nearly the same unit and love it. It brought my Bose amp to life. My installer mounted the mic on top of the trim piece along the side of the windshield. That piece of trim pops off and the wire is easily ran underneath. Also set the mic gain on that receiver down to 5. It defaults to 8 or 9 and doesn't work well on that setting
here is the fully installed unit. Yes, I did not do anything with the microphone cord except TAPE IT TO THE CONSOLE. Very slightly indeed. Then again, it is a 14 year old car and I am a klutz. I might to look at this again in the future, but need the car this week.
More updates. Thanks to my friend Sam, I learned that the RCA jacks output from the head unit was lame (that ohm thing or whatever discussed elsewhere in the forum). So I cut the RCA jacks off of the adapter wiring harness, and used the remaining splinters of wire to connect to the speaker output wires of the head unit. Fiddly work. And realized that Sam was right - the sound was MUCH louder and clearer hard-wired. Very pleased with the results.
Now with the microphone. I could not find an easy exit point for the wire. Being that I am happy just getting the thing installed without blowing up the car or another car or even the house () I just took the easier, softer way and taped the wire to the dashboard. I mounted the microphone on the steering column. It seems to work well enough at parking lot speeds. I will be on interstates for 500 miles on Wednesday and Saturday so will have plenty of time to play with microphone levels.
If I ever go back inside the console, I will try to find a neater way to run the wire.
Did you use the Metra 70-1786 harness? Running speaker level outputs into the BOSE amp, which is expecting some sort of line level signal, certainly can't be a good thing.
Uh oh. That is the harness I used. So I should get another one and revert back to RCA jacks? I do not understand any of this which is why I posted here. I saw bits and pieces of this install and could not figure out which applied to this vehicle/head unit specifically.
OK so that will will mean I easily have surpassed cost/benefit of having it done by a knowledgeable professional!
Hey garytalda I have a 1998 E320 (W210) and I put an aftermarket DVD player in mine. I used the Metra #70-1784 wiring harness. It was a straight plug and play when i removed the old Beker one. All you have to do is take the radio hardness and match the wires to the Metra #70-1784 except that the Red power from Metra #70-1784 and Yellow on the radio harness match and again the red on the radio harness for the Yellow on the Metra #70-1784. It as VW harness. Other than that the rest of the wires match up the colors.
If you have any more q's send me a message, will help out as much as I know.
@niral114 have you considered swapping the radio with the hvac controls. When I got my car the setup was like yours with the screen blocking the hvac controls. I disconnected both of them and swapped positions so I can use the hvac without closing the screen every time.
@illest, I wanted to for the longest time and I tried but the radio depth is too big for the depth of the hvac controls. Did you have trouble swapping. I might take a crack at it again in the spring, winter here in New Jersey has been terrible and haven't gotten time to work on that part. You have any tips on the swap because I saw the wiring its a straight disconnect and reconnect but my issue is the depth. Did you have any space issues. When I tired to swap them initially I saw the hvac space was less than the radio depth, not sure if that was in my 1998. I really want to swap them.
Thanks I got the Matra 70-1786 (don't know what the difference is). Yellow-yellow, blue-blue, black-black, and red from cigarette lighter. did you just use the RCA jacks output or did you hardwire the speakers? In listening I really think I did a bad, bad thing using speaker wire output as with volume at like 8 it is loud enough for this rapidly-approaching-elderly dude.
In the Metra #70-1784 there are no RCA outputs. Its just straight match wiring color for color except the yellow goes to red and red goes to yellow.
The radio harness I connected that to the Metra #70-1784. This harness doesnt have RCA output. Its just straight wiring but since its a VW harness the Yellow from the #70-1784 goes to the Red radio harness and Red from the #70-1784 goes to the yellow from the radio harness. Rest just match the colors.
I never used the #70-1786 so not too familiar with the RCA option.
Yes I changed the unit but kept the bose amp.
I did add in a sub amp in the trunk but that audio is used by RCA's in the back of the radio.
I haven't messed with putting a new head unit yet into my Bose W210, but generally speaking, you don't want to run speaker level outputs into the input of any amplifier, but it sounds like that's what many of you guys did?
If this is the way to do it, I may just get a 17-1784 harness and do mine the same way when I swap head units....
The harness 17-1784 allows you to use the factory wiring so you don't have to run new wires. The only new wires I ran was an RCA set along with the remote line from the back of my radio to a sub amp because I put 2 subs in my trunk.
The harness 17-1784 allows you to use the factory wiring so you don't have to run new wires. The only new wires I ran was an RCA set along with the remote line from the back of my radio to a sub amp because I put 2 subs in my trunk.
I didn't ask a thing about running new wires. I asked, in my previous post, if you're stating that you ran SPEAKER level outputs from the head unit, into the stock harness, which goes through the car to the trunk, to the INPUT of the BOSE amp? Thus you're driving the amp (which typically expects a line level signal) with a speaker level signal?
I haven't messed with putting a new head unit yet into my Bose W210, but generally speaking, you don't want to run speaker level outputs into the input of any amplifier, but it sounds like that's what many of you guys did?
If this is the way to do it, I may just get a 17-1784 harness and do mine the same way when I swap head units....
This is NOT the way to do this. You should never run speaker level output to an amp that is not designed to accept this type of signal. If you choose to go this route, you should use a LOC (Line Output Converter). This will convert the speaker level to line level. A head unit with a 4volt output on the pre amp to the Bose amp works perfectly.
I haven't messed with putting a new head unit yet into my Bose W210, but generally speaking, you don't want to run speaker level outputs into the input of any amplifier, but it sounds like that's what many of you guys did?
If this is the way to do it, I may just get a 17-1784 harness and do mine the same way when I swap head units....
I used the 17-1786. 4 connections to head unit required : yellow, black, and blue all came from 1786, red in my case came from cigarette lighter as there was no corresponding power input on the original Mercedes wiring harness. I am the idiot who originally used the rca jacks, thought it was 'too quiet', and then cut the rca jacks to wire the speaker outputs on the head unit to the previously rca jacks.
Note if you are skilled there is also a dimmer wire (orange) available on some new head units that you can get from somewhere else in the dashboard. I am not skilled and am OK with how bright the new Kenwood is at night so have no desired to go further.
I do not have steering wheels controls but given how icky those buttons are anyway I don't mind.
I used the 17-1786. 4 connections to head unit required : yellow, black, and blue all came from 1786, red in my case came from cigarette lighter as there was no corresponding power input on the original Mercedes wiring harness. I am the idiot who originally used the rca jacks, thought it was 'too quiet', and then cut the rca jacks to wire the speaker outputs on the head unit to the previously rca jacks.
Note if you are skilled there is also a dimmer wire (orange) available on some new head units that you can get from somewhere else in the dashboard. I am not skilled and am OK with how bright the new Kenwood is at night so have no desired to go further.
I do not have steering wheels controls but given how icky those buttons are anyway I don't mind.
It was too quiet because this head unit only has 2.5 volts on the pre amp output. The Bose amp needs 4volts. This info is well documented in the various MB forums. You really need to wire in a LOC to keep from burning your amp up. Even though the amp is located in an open area (trunk), and the amp has sizable cooling fins it is only a matter of time until your amp is toast. JMHO, take it or leave it.
This all sounds correct now. You NEVER run a speaker level output into an amplifier that is designed for line level inputs. From what I can tell, the 17-1786 is the harness to use, and you may need to use ground loop isolators to avoid the "popping" (and potentially alternator whine).
If you have a low output (under 4V these days) head unit, I'm sure it may seem "too quiet," but, again, while it may sound "louder" the way you have it, I'm just going to go out on a limb here and say that it's not going to be good for the BOSE amp long term.
Let me say I am EXTREMELY grateful for both of your input and your patience.
However, I truly am uneducated and unskilled and need to be spoken to in clear, unambiguous terminology. I have ordered another harness. However, AS I UNDERSTAND IT, the stereo just isn't going to ruin my hearing using the RCA jacks (volume will be less than thrilling). What exactly is a line output converter (LOC?). I guess it is another thing that has 8 speaker inputs at "line" volume and converts it to 8 speaker outputs at what ? So if I install one I will have 16 more connections to wire?
This all sounds correct now. You NEVER run a speaker level output into an amplifier that is designed for line level inputs. From what I can tell, the 17-1786 is the harness to use, and you may need to use ground loop isolators to avoid the "popping" (and potentially alternator whine).
If you have a low output (under 4V these days) head unit, I'm sure it may seem "too quiet," but, again, while it may sound "louder" the way you have it, I'm just going to go out on a limb here and say that it's not going to be good for the BOSE amp long term.
that I would use in the "Line Out" position. I think.
It is certainly starting to look out of my league, especially because the output is not calibrated by volts or ohms or whatever, but by ear, i.e., when it sounds loud enough, then it is right?
You either need a different head unit, with higher voltage output on the preamp (RCA) outputs to use a new 17-1786 harness with (and likely, to avoid "pops" and whine, a ground loop isolator), or you can use a line output converter (this converts from SPEAKER level to LINE level) between your current head unit and new 17-1786 harness, so that you can use your current head unit.
The converter you linked to on Crutchfield would work.
It is certainly starting to look out of my league, especially because the output is not calibrated by volts or ohms or whatever, but by ear, i.e., when it sounds loud enough, then it is right?
Maybe not. It just takes a little thought and planning. The support group at Crutchfield is very good, and provide help and install support for all their products. Give them a call, tell them what you have done and ask what you need to do to correct it.
Just a thought, and not sure this will work. It may be possible to connect the LOC to the pre-amp outs, and use the gain controls on the LOC to boost the volume. I am not sure, but this may reduce some of the cutting and splicing.
Well the hole gets deeper but I keep diligently digging. So I called Crutchfield. they did not know the RCA output of that particular LOC as it was not in documentation. So I found that company and discovered max output was only 2 volts - so even though Crutchfield told me it would have worked, well, yes, but softly.
So I then tortured myself and found this :
Which can be adjusted / tuned to 4 or even 8 volt output.
There is a similar thread going on in benzworld. There users are claiming that speaker output is safe to feed into the Bose amp without an LOC!
So I said to myself, "self, what the hell is going to the speakers? Why it is MAX 50 watts per channel. So what is the voltage on that? Why, that would be volts=watts/amps. So if we want a maximum of 4 volts, then amps has to be 12.5 OR GREATER. I don't actually know amps here but suspect that it is not greater than 7 or 8 so speaker output could easily be pushing 7 or 8 volts WHEN VOLUME CRANKED. But self, remember you don't know what you are talking about".
So it seems to me, if it is just me in the car listening to traffic or Nancy Gross then there is no risk to the amp. However, if I am listening to Limbaugh or if I have teenagers (which I have 2 boys) who drive the car with the volume cranked and the bass cranked (which they do), then I am pretty much guaranteed to blow the amp without the LOC. Does this make any sense at all?
Probably not but I am barbeque-drunk and going to have meat sweats.
Midwood Smokehouse barbeque in Charlotte NC is some damn fine barbeque. Might not know a thing about electrical engineering but I do luv me some good barbeque.
Honestly, I'm surprised that you haven't blown up the BOSE amp already. I can assure you, that if you take any aftermarket car amp, or try this with your home audio gear, and take the output from a receiver (speaker level) and hack up a set cables to put that into the input of a power amp, that said power amp will blow up within about 2 seconds.
Pre-outs on car head units are marketed in volts (4V/ 8V/ etc), but the signal current is measured in milliamps (i.e. 1/1000 amp). Speaker level outputs can easily have current that is measured in multiple amps (and frequently at greater than 25V). So, to put this into a wattage comparison, a line level signal might be a few watts (at most, likely much less), whereas a speaker level signal can easily be 25 or 50 watts.
I hope that this explains why this is an issue.
As far as LOCs, that PAC audio unit would likely be a much better option.
02-22-2015, 07:28 PM
) I just took the easier, softer way and taped the wire to the dashboard. I mounted the microphone on the steering column. It seems to work well enough at parking lot speeds. I will be on interstates for 500 miles on Wednesday and Saturday so will have plenty of time to play with microphone levels. 
