2003 CDR23/BOSE/MOST replacement - misc install notes

[sanjeev]

Hi all,

I am almost thru the replacement of a CDR23 / BOSE amplifier (2003 MOST bus) , and wanted to share

some of my install notes. I have gained a lot of insight by reviewing previous posts, and hopefully, can

add some more to the collective wisdom on this topic!

Briefly, I was able to successfully interface a Nakamichi CD400 HU and ARC Audio Mini 4-ch amplifier

to the factory wiring harness using an Autoleads PC2-95-4 connector. NO CUTTING/SPLICING of factory

wiring was needed, which was a key consideration for me.

Result - It works, and sounds noticeably better than stock (w/ the factory spkrs). However, the factory spkrs' deficiencies

have now been highlighted, so me-thinks a decent set of Focals, Morels, Dynaudio or the like is the next order of business!

Anyway, if anyone is interested in details, please see attached PDF. Note, this is NOT a full DIY tutorial - if you

are not familiar w/car stereo installations, I would recommend letting a shop handle this. I purchased this amp from

Rod Birch (Car Audio Innovations) and his advise and help was indispensible for me to get thru this project.

Thanks,

- Sanjeev

Amp-HU-install.pdf

PS: I would highly recommend Rod Birch - he is extremely knowledgeable about these cars and their ins/outs

relative to stereo installs.

[Dharn55]

Good info and DIY. However you have now discovered that the weakest link in the system is really the speakers. Doesn't really matter what head unit or amp you have, anything will sound pretty poor through the OEM speakers. I always tell people to start with the speakers first.. I have Focals all the way around and a JL Audio amp, still have the stock Head unit and CD changer and will put my system up against anything that is using the OEM speakers and believe my system will win hands down.

[johonole]

Good info- I am in the process of installing a dbl din in my 2003 most- Bose. I would love to find the wiring diagram you spoke of in your post, but can't find it.

Any clues?

[sanjeev]

Good info- I am in the process of installing a dbl din in my 2003 most- Bose. I would love to find the wiring diagram you spoke of in your post, but can't find it.

Any clues?

I used Pins A4, A5 and A8 to connect the HU. You can get a compatible ISO-DIN harness adapter from most car stereo stores (I used a BEST KIT BHA1784).

Hope this helps

- Sanjeev

CDR23-connectors.pdf

[johonole]

Sanjeev- thanks for the reply. I pulled out the CDR 23 radio and installed a Pioneer double din. Had to move AC and remove CD drawer. I spliced the speaker outputs on the Pioneer to the speaker wires on the original amp in the trunk. It works and sounds good. I left power to the original amp in the trunk, but have no audio input to it. I am now wondering if this will cause a problem with the system in time.

The reason I left the power to the original amp was I used the headlight switched wire from the yellow plug (that pluged into the CDR 23 radio and then ran to the original amp) to feed the new Pioneer headlight switch hook up. Not sure the original amp needs power for this headlight switch wire to work, but not sure it doesn't.

Your original PDF install post said you used the wiring diagram for the Bose/most system that was located on this forum for your install.

I searched this forum, and could not find the diagram.

Can you tell me where to find it? I think it may help me clear up some of questions.

[sanjeev]

Sanjeev- thanks for the reply. I pulled out the CDR 23 radio and installed a Pioneer double din. Had to move AC and remove CD drawer. I spliced the speaker outputs on the Pioneer to the speaker wires on the original amp in the trunk. It works and sounds good. I left power to the original amp in the trunk, but have no audio input to it. I am now wondering if this will cause a problem with the system in time.

The reason I left the power to the original amp was I used the headlight switched wire from the yellow plug (that pluged into the CDR 23 radio and then ran to the original amp) to feed the new Pioneer headlight switch hook up. Not sure the original amp needs power for this headlight switch wire to work, but not sure it doesn't.

Your original PDF install post said you used the wiring diagram for the Bose/most system that was located on this forum for your install.

I searched this forum, and could not find the diagram.

Can you tell me where to find it? I think it may help me clear up some of questions.

I was referring to the CDR23 pinout diagram I posted earlier (primarily). You can also review a pinout diagram for the trunk-mounted M680 BOSE amplifier (attached).

However once you gain access to the pins from the plug-in harness adapter, it is simple enough to inspect and test each pair to identify the connected speakers.

Hope this helps.

Good Luck.

- Sanjeev

PS: After reading multiple audio-installation DIYs, I decided to ground the HU directly to the chassis (instead of using the GND wire in the factory CDR23 plug A).

Better to avoid ground loop induced noise, I'm told. (Curiously, I didn't experience any significant or noticeable noise either way, YMMV.)

[cayvman]

Good info and DIY. However you have now discovered that the weakest link in the system is really the speakers. Doesn't really matter what head unit or amp you have, anything will sound pretty poor through the OEM speakers. I always tell people to start with the speakers first.. I have Focals all the way around and a JL Audio amp, still have the stock Head unit and CD changer and will put my system up against anything that is using the OEM speakers and believe my system will win hands down.

Dharn55-can you tell me more about your speaker upgrade to Focals. Size,model. Did you have the Bose sound system?

[dman66]

Excellent guide...

I have a couple of questions if you don't mind

You're using a 3-way crossover - how is it wired to the front speakers since they already have a crossover on the dash speaker don't they?

How did you wire the rear speaker of the HU together for the fill?

Where did you get the Autoleads connector from?

Hi all,

I am almost thru the replacement of a CDR23 / BOSE amplifier (2003 MOST bus) , and wanted to share

some of my install notes. I have gained a lot of insight by reviewing previous posts, and hopefully, can

add some more to the collective wisdom on this topic!

Briefly, I was able to successfully interface a Nakamichi CD400 HU and ARC Audio Mini 4-ch amplifier

to the factory wiring harness using an Autoleads PC2-95-4 connector. NO CUTTING/SPLICING of factory

wiring was needed, which was a key consideration for me.

Result - It works, and sounds noticeably better than stock (w/ the factory spkrs). However, the factory spkrs' deficiencies

have now been highlighted, so me-thinks a decent set of Focals, Morels, Dynaudio or the like is the next order of business!

Anyway, if anyone is interested in details, please see attached PDF. Note, this is NOT a full DIY tutorial - if you

are not familiar w/car stereo installations, I would recommend letting a shop handle this. I purchased this amp from

Rod Birch (Car Audio Innovations) and his advise and help was indispensible for me to get thru this project.

Thanks,

- Sanjeev

Amp-HU-install.pdf

PS: I would highly recommend Rod Birch - he is extremely knowledgeable about these cars and their ins/outs

relative to stereo installs.

[sanjeev]

Excellent guide...

I have a couple of questions if you don't mind

You're using a 3-way crossover - how is it wired to the front speakers since they already have a crossover on the dash speaker don't they?

How did you wire the rear speaker of the HU together for the fill?

Where did you get the Autoleads connector from?

Hi all,

I am almost thru the replacement of a CDR23 / BOSE amplifier (2003 MOST bus) , and wanted to share

some of my install notes. I have gained a lot of insight by reviewing previous posts, and hopefully, can

add some more to the collective wisdom on this topic!

Briefly, I was able to successfully interface a Nakamichi CD400 HU and ARC Audio Mini 4-ch amplifier

to the factory wiring harness using an Autoleads PC2-95-4 connector. NO CUTTING/SPLICING of factory

wiring was needed, which was a key consideration for me.

Result - It works, and sounds noticeably better than stock (w/ the factory spkrs). However, the factory spkrs' deficiencies

have now been highlighted, so me-thinks a decent set of Focals, Morels, Dynaudio or the like is the next order of business!

Anyway, if anyone is interested in details, please see attached PDF. Note, this is NOT a full DIY tutorial - if you

are not familiar w/car stereo installations, I would recommend letting a shop handle this. I purchased this amp from

Rod Birch (Car Audio Innovations) and his advise and help was indispensible for me to get thru this project.

Thanks,

- Sanjeev

Amp-HU-install.pdf

PS: I would highly recommend Rod Birch - he is extremely knowledgeable about these cars and their ins/outs

relative to stereo installs.

[gu9cci]

True with the speakers must be upgraded.i did 3way rainbow vanadium speakers and crossovers (tweeter,midrange,midbass) and mounted in stock speaker grills with 6.5 inch in doors with new buffles.I did also dynamat sound deadening in doors for better midbass reproduction.Got pioneer premier headunit 800PRS and TRU TECHNOLOGY AMP.

[Dennis C]

I agree on the speakers too. I've got Focals all the way around too, with a Focal amp. They are just really starting to "open up" since they were installed, and the sound is great. I'm extremely pleased with them.

[Terry-986-2.7-5spd]

Hi guys. Thanks for all your information posted here, it’s been very helpful. I am trying to work out how I might install a pair of rear speakers on my 2002 986 that has a CDR-23 with MOST bus and the yellow C1 connector on it only has 4 pins with wires that are black, yellow, green and white with a red stripe. From the diagram you posted Sanjeev, it appears that these are titled ‘CAN comfort high’ and ‘CAN comfort low’, ‘wake up diagnosis’ and ‘key code in’ but I can’t find any reference as to what this means, do you know? I presume that all the audio is getting to the amp in the trunk via the MOST bus as I don’t have an audio out connector on the radio but I also can’t tell which amp pins are doing the audio out from the trunk as my manual doesn’t seem to cover the 2002 wiring diagrams. Would appreciate any advice if you have the opportunity please. 

[987_RDC]

The ISO pin out can differ depending on radio model. You should check other 986 CDR-23

 

For 996 does anyone know if the BOSE amp adapter PC2-95-4 is just another PN for the CT20PO01 adapter?

[987_RDC]

CT20P001 arrived from the UK. Ordered that since it was cheaper. Works great for the 996 BOSE amp (MOST style) connector to access the stock speak output wires. I just had to adjust two pins since I think it is setup for a Cayenne and also snip off the "guiding nubs" since it would not fully seat.

 

Working awesome for the BOSE amp replacement. (BOSE amp missing from used car purchase but looking for clean install vs. cut stock wires) The front dash are Diamond s6.0 4ohm mids with 6ohm tweeters. (4 sets of speaker wires run to the front trunk). The car came with Nokia M680 rear set of speakers at 4ohm. Running an aftermarket deck that came in the car but switched it to "Network mode" where 3 RCA are mid/high/sub. (instead of Front/Rear/Sub)

 

Running a Kicker 46CXA6605 amp where Amp 1 is parallel dash mid and rears @ 2ohm. Amp 2 is mono L with the tweeters in parallel for 3ohm. Door BOSE R, cabriolet sub, door BOSE L in series for 5ohm on sub channel.

 

Pics of the adapter before snipping off the circles:

Edited May 24, 2021 by 987_RDC