this is mainly for UKInstaller
I need a wiring diagram for 1994 Mercedes 500 SL with factory installs;
Alpine CM 2194 head unit (looks just like the Becker...(both made for MBZ)
Bose R 129 4 channel amplifier
no sound / intermittent sound on left front. trying to troubleshoot. want to keep original equip. any in do-it-yourself repairs / parts will be appreciated.
xtc2c
Replies (8)
ttocs on 02/4/2006 16:39:12
does it have the fader on the consol? I am pretty sure you have to bypass that due to impedence problems.
Unfortunatly my book does not give deck wiring.
xtc2c on 02/4/2006 18:22:13
on the SL 500 model...there is only a left and right balance and no fader for front and read. I read that this was by design when Alpinf designed the system. see this link http://www.carstereohelp.com/mercedes.htm
UKinstaller on 02/4/2006 20:32:23
unfortunately my friend i do not have wire colors available for your car. i just checked 3 different references and can't find anything.
that being said, i have seen this problem in 2 different mercedes, and both of them turned out to be the head unit. bad outputs to individual channels and so forth.
yank the deck out, have it sent to a reputable repair shop and see if they can do anything if you want to keep the factory equipment.
as a last resort, and it could take a while, you could do some probing and figure out a way to maybe wire your front left speaker in with your back left speaker in series, eliminating whatever bad channel you have on your deck and/or amplifier, if it's even possible. if you do that, you'll want to do the right side speakers in the same manor for even volume. it won't be as loud, but it could fix your problem.
swez, ttocs you think this would work??
-UK
swez on 02/4/2006 21:15:16
Testing the Factory HU would be my choice initially. There might be a simple solution like a loose wire or bad ground is all. That can easily be fixed.
However, if the HU has internal problems, now you have a fork in the road to deal with...
1. Have the factory HU repaired (expensive and lost time)
2. Install an Aftermarket HU and see if there are kits out there to match up the new HU to the factory amps (assuming the factory amps are OK)
Does this factory HU have other features that tie into alarm or other functions withing the car? Most likely, it will. Take that into consideration as well.
Swez
xtc2c on 02/4/2006 22:50:43
thanks you guys..this helps. I tested the Amp separately by connecting directly to the left and right channel individually and did the same on the HU. On the Amp, I think the test is not reliable because I was tapped into the harness and it still connects to the HU and to the speakers. results the same in all tests. I looked for a bad wire and lose ground but stillno action.
Strangely enough, when I connect the Antenna to the back of the HU it cuts off the music and lowers the antenna and no sound is heard at all. If I disconnect the antenna, it plays only thru the right channel.
XTC2C
swez on 02/5/2006 06:36:44
Interesting comment on the antenna issue. There probably is a connection between that and other system performance issues. THINK
The antenna is often part of the grounding path for the HU. The HU also has a harness ground and perhaps another grounding point to the metal body as well. The amplifier is often grounded to the body as well. If we lose a ground path, the system will act up in several ways.
Also, the antenna goes up, only when the AM/FM modes are used. When switching to CD's, the antenna usually gets a signal to come back down. Does that seem to be working properly now?
Swez
ttocs on 02/5/2006 11:48:05
yea I don't understand the antenna thingy(to get technical).
I/we need to know EXACTLY what ya did. Keys on or off, deck plugged in and powered or off??
UKinstaller on 02/5/2006 21:19:16
when it comes to mercedes i almost always recommend just replacing the entire sound system. by this i mean a new head unit with new power / ground and running new speaker wire to each speaker. this completely bypasses any mercedes garbage that can come to give you a huge pain in the butt.
the labor isn't too bad. you sound technical, and you can probably get away with using the stock speakers even though i wouldn't recommend it. also, there is a wire tied into the factory deck that must stay grounded or else you will have problems with the factory alarm system going off at random.
aftermarket radios always look AWESOME in any mercedes because they fit with no probablem and they always look great with all the wood grain and so forth. i can even tell you how to keep the balance switch in the center console if you want to.
the reason i recommend this route is because one, mercedes repair costs are astronomical, and two, it will make your sound system sound a LOT better for a sweet car that deserves much better sound than what it came with.
always remember that bose is just a name. in all reality, the only bose system i've ever been impressed with is in any newer (2003+) cadillac, especially the escalade and CTS. sweet systems, but other than that....
no highs, no lows, it must be bose!
-UK
I need a wiring diagram for 1994 Mercedes 500 SL with factory installs;
Alpine CM 2194 head unit (looks just like the Becker...(both made for MBZ)
Bose R 129 4 channel amplifier
no sound / intermittent sound on left front. trying to troubleshoot. want to keep original equip. any in do-it-yourself repairs / parts will be appreciated.
xtc2c
Replies (8)
ttocs on 02/4/2006 16:39:12
does it have the fader on the consol? I am pretty sure you have to bypass that due to impedence problems.
Unfortunatly my book does not give deck wiring.
xtc2c on 02/4/2006 18:22:13
on the SL 500 model...there is only a left and right balance and no fader for front and read. I read that this was by design when Alpinf designed the system. see this link http://www.carstereohelp.com/mercedes.htm
UKinstaller on 02/4/2006 20:32:23
unfortunately my friend i do not have wire colors available for your car. i just checked 3 different references and can't find anything.
that being said, i have seen this problem in 2 different mercedes, and both of them turned out to be the head unit. bad outputs to individual channels and so forth.
yank the deck out, have it sent to a reputable repair shop and see if they can do anything if you want to keep the factory equipment.
as a last resort, and it could take a while, you could do some probing and figure out a way to maybe wire your front left speaker in with your back left speaker in series, eliminating whatever bad channel you have on your deck and/or amplifier, if it's even possible. if you do that, you'll want to do the right side speakers in the same manor for even volume. it won't be as loud, but it could fix your problem.
swez, ttocs you think this would work??
-UK
swez on 02/4/2006 21:15:16
Testing the Factory HU would be my choice initially. There might be a simple solution like a loose wire or bad ground is all. That can easily be fixed.
However, if the HU has internal problems, now you have a fork in the road to deal with...
1. Have the factory HU repaired (expensive and lost time)
2. Install an Aftermarket HU and see if there are kits out there to match up the new HU to the factory amps (assuming the factory amps are OK)
Does this factory HU have other features that tie into alarm or other functions withing the car? Most likely, it will. Take that into consideration as well.
Swez
xtc2c on 02/4/2006 22:50:43
thanks you guys..this helps. I tested the Amp separately by connecting directly to the left and right channel individually and did the same on the HU. On the Amp, I think the test is not reliable because I was tapped into the harness and it still connects to the HU and to the speakers. results the same in all tests. I looked for a bad wire and lose ground but stillno action.
Strangely enough, when I connect the Antenna to the back of the HU it cuts off the music and lowers the antenna and no sound is heard at all. If I disconnect the antenna, it plays only thru the right channel.
XTC2C
swez on 02/5/2006 06:36:44
Interesting comment on the antenna issue. There probably is a connection between that and other system performance issues. THINK
The antenna is often part of the grounding path for the HU. The HU also has a harness ground and perhaps another grounding point to the metal body as well. The amplifier is often grounded to the body as well. If we lose a ground path, the system will act up in several ways.
Also, the antenna goes up, only when the AM/FM modes are used. When switching to CD's, the antenna usually gets a signal to come back down. Does that seem to be working properly now?
Swez
ttocs on 02/5/2006 11:48:05
yea I don't understand the antenna thingy(to get technical).
I/we need to know EXACTLY what ya did. Keys on or off, deck plugged in and powered or off??
UKinstaller on 02/5/2006 21:19:16
when it comes to mercedes i almost always recommend just replacing the entire sound system. by this i mean a new head unit with new power / ground and running new speaker wire to each speaker. this completely bypasses any mercedes garbage that can come to give you a huge pain in the butt.
the labor isn't too bad. you sound technical, and you can probably get away with using the stock speakers even though i wouldn't recommend it. also, there is a wire tied into the factory deck that must stay grounded or else you will have problems with the factory alarm system going off at random.
aftermarket radios always look AWESOME in any mercedes because they fit with no probablem and they always look great with all the wood grain and so forth. i can even tell you how to keep the balance switch in the center console if you want to.
the reason i recommend this route is because one, mercedes repair costs are astronomical, and two, it will make your sound system sound a LOT better for a sweet car that deserves much better sound than what it came with.
always remember that bose is just a name. in all reality, the only bose system i've ever been impressed with is in any newer (2003+) cadillac, especially the escalade and CTS. sweet systems, but other than that....
no highs, no lows, it must be bose!
-UK
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