DCM: AKA (Expletive!)

[TX '90 ZR1]

Always like to have a project going on my '90 and I am down to the "picky" stuff. Decided to remove the passenger seat to repair the lumbar system and had the brainstorm to take out the DCM as Dr. Don tells me this is why my radio is not working.
I read all the horror stories and even checked my FSM. (My original '90 red cover FSM has bad information. It is totally useless for removing the DCM).
Had the covers off the dash in a couple of minutes and could see the 3 connectors on the passenger side as well as the nut that needed to be removed. Another couple of minutes and I had the connectors loose as well as the nuts on both sides using a ratchet end box wrench. I was thinking, "This is not near as bad as the stories, slide it forward and work it out". WRONG!! Nowhere in the research I did was any mention of electrical connectors on the drivers side of the DCM. These two connectors were by far the worst part of getting the box out. There is about half enough room to get ahold of them, and being in there for nearly 30 years they were not giving up easily. The box will not slide forward 'till these connectors are loose. I considered explosives a couple of times.
After getting the drivers side connectors loose, was able to work the box forward and out towards the passenger side.
Anybody know who the rocket scientist is that decided the box needed an aluminum bracket sticking out the front? That 1 inch would make removing a lot easier. If it is a heat sink or something, I think I could have figured out a better way to do it.
As I was looking the box over after removal, I noticed the label said "Made in Kokomo". Yes, "Kokomo!!!". Considering what I went through to get it out, I took it as a really bad diss on a good Beach Boys song. It was not funny!
:censored:

[Dynomite]

DO not break those two plastic "L" tabs on each side of the CDM (Control Data Module) black plastic Cover :cheers:

See #3...……...Post # 139---Bose (Radio, Speaker Amps, CDM) Replace (https://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-7.html#post1585219757)

There is a video there in Post #139 as well......have fun....
Oh......when you install another CDM plug it in (all electrical connections)
before you complete the installation to make sure that was the issue :thumbsup:

[TX '90 ZR1]

DO not break those two plastic "L" tabs on each side of the CDM (Control Data Module) black plastic Cover :cheers:

See #3...……...Post # 139---Bose (Radio, Speaker Amps, CDM) Replace (https://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-7.html#post1585219757)

There is a video there in Post #139 as well......have fun....
Oh......when you install another CDM plug it in (all electrical connections)
before you complete the installation to make sure that was the issue :thumbsup:

Thanks for the input Dynomite.
I watched the video and read the posts several times for guidance.
And I will definitely hook the DCM up for a test run before doing the complete re-install.

[indy91zr1]

Always like to have a project going on my '90 and I am down to the "picky" stuff. Decided to remove the passenger seat to repair the lumbar system and had the brainstorm to take out the DCM as Dr. Don tells me this is why my radio is not working.
I read all the horror stories and even checked my FSM. (My original '90 red cover FSM has bad information. It is totally useless for removing the DCM).
Had the covers off the dash in a couple of minutes and could see the 3 connectors on the passenger side as well as the nut that needed to be removed. Another couple of minutes and I had the connectors loose as well as the nuts on both sides using a ratchet end box wrench. I was thinking, "This is not near as bad as the stories, slide it forward and work it out". WRONG!! Nowhere in the research I did was any mention of electrical connectors on the drivers side of the DCM. These two connectors were by far the worst part of getting the box out. There is about half enough room to get ahold of them, and being in there for nearly 30 years they were not giving up easily. The box will not slide forward 'till these connectors are loose. I considered explosives a couple of times.
After getting the drivers side connectors loose, was able to work the box forward and out towards the passenger side.
Anybody know who the rocket scientist is that decided the box needed an aluminum bracket sticking out the front? That 1 inch would make removing a lot easier. If it is a heat sink or something, I think I could have figured out a better way to do it.
As I was looking the box over after removal, I noticed the label said "Made in Kokomo". Yes, "Kokomo!!!". Considering what I went through to get it out, I took it as a really bad diss on a good Beach Boys song. It was not funny!
:censored:

probably kokomo indiana

[BigJohn]

Delphi electronics Kokomo Indiana

[TX '90 ZR1]

I realized after a while it was Kokomo, Indiana. However, that was not my thought just after getting it out!
Have a great one guys.
:dancing

[Z51JEFF]

Wasn’t that a nightmare? At some point it was moved to one of the bins behind the seat. One thing you want to make sure of is make sure all of the plugs go back together with all the connectors in their cavities. When I did mine years ago when I plugged everything back together I didn’t notice that one of the connectors for the ABS got pushed out of the plug,took me forever to find the issue with the ABS. I unplugged everything that passes under the CDM.

[TX '90 ZR1]

Wasn’t that a nightmare? At some point it was moved to one of the bins behind the seat. One thing you want to make sure of is make sure all of the plugs go back together with all the connectors in their cavities. When I did mine years ago when I plugged everything back together I didn’t notice that one of the connectors for the ABS got pushed out of the plug,took me forever to find the issue with the ABS. I unplugged everything that passes under the CDM.
Thanks for the input Jeff.
I visited with Dr. Don extensively about removing it. In fact, I tried to get him to agree to remove and install it as he is just a few hours from me. He as kindly as he could told me he was NOT doing it!!
He explained to me how to get it out without disconnecting all the wires underneath the CDM. I did it as he suggested. It might or might not have been easier with the wires loose. Either way, it was not a pleasant experience to remove. Keeping my fingers crossed I can get it back in without throwing hard items into breakable objects!!
:cheers:

[Z51JEFF]

Back when I did mine,while working on this thing,laying on my back in the passenger foot well,looking up into a 9 inch square hole I reliezed,I couldn’t see for sh!t. I started wearing glasses after that. That was the most challenging job I’ve ever done.

[TX '90 ZR1]

Well, I got the DCM back in today.
Going back in was actually less painful than removing it. I think being familiar with how it goes made everything go better. Still not an easy job though.
After doing one, I think I could remove it without getting on my back and looking up from underneath. Everything on the drivers side can be unhooked by feel. Everything on the passenger side can easily be seen looking up under the fuse panel. I removed and installed by sliding it out and in under the fuse panel.
The good news is that I now have a good DCM in the car. The bad news is that I still don't have tunes. Now all you hear is a buzz from the speakers. Dr. Don says that now since we have a working DCM we have discovered that the amps are out in the speakers.
I'll get those out and let him do his magic. Removing the speakers will be a walk in the park compared to the DCM.
Will keep everyone posted.

[Reichert]

Before I learned about Dr. Don from the forums here, on my own research I found these guys in Florida that specialize in Corvette stereo repair. I removed and boxed up the DCM, all 4 amps, and head unit and mailed the whole kit to them. I had it back within a week, and everything worked like new. Every bit of it turned out to have some problem or another, especially the amps. Cost was $700. $100 of that was extra to have a 3/8" stereo line-in added. Lifetime warranty on amps; 1 year on the tuner.

http://www.carstereoremoval.com/htm/stereoremovalCorvette.htm

There are some good videos of removing the components on their website as well: http://www.carstereoremoval.com/htm/stereoremovalCorvette90_96P.htm

And yes .. despite all of the how-to videos and planning .. extracting the DCM out from under the dash was a joyless experience that I hope never to have to repeat.

[TX '90 ZR1]

Stephen:
I got good reports on them as well. I decided on Dr. Don for a few reasons.
First, he was closer, which is not really a big deal now as easy as it is to ship cross country.
Second, he was highly recommended on the forum.
Third, and this is the one that sealed the deal. I called his published number and Don himself answered. He was kind enough to spend about 30 minutes on the phone explaining how he advised would be the best way to approach the radio issues. He went into great detail on removing the DCM even though I could not convince him to let me bring the car for him to remove and re-install.
My continued experience has been the same. I call, he answers and spends the time to make sure everything is understood.
I think he may be a bit more expensive than others, but the personal service, in my opinion, more than makes up for it.
If I wasn't spending on the ZR-1 & V-Rod I would be blowing it on whiskey and wild women. I think the rides are the better choice. ;)

[Reichert]

I likely would have used Dr. Don also if I had spent more time on the forums before diving into it. At any rate, it's great that for this particular system, there are at least a couple of good choices.

The only thing I'm not happy with is the fact that the antenna is deployed even when the line-in is in use. To work around that I was thinking of adding an separate power switch for the antenna. Did you happen get Dr. Don to add a line-in added to your DCM?

[Z51JEFF]

I’ve read that there are several cars out there that used the same Delco system,Nissan Maxima is one I think,you can easily find these in the wrecking yards.

[TX '90 ZR1]

I likely would have used Dr. Don also if I had spent more time on the forums before diving into it. At any rate, it's great that for this particular system, there are at least a couple of good choices.

The only thing I'm not happy with is the fact that the antenna is deployed even when the line-in is in use. To work around that I was thinking of adding an separate power switch for the antenna. Did you happen get Dr. Don to add a line-in added to your DCM?

Stephen,
I'm not really up to speed on some of the newer audio choices. Dr. Don did not mention anything about adding a "line in" to the DCM.
I think he does some kind of modification to the control head to allow input from different sources. Not sure what they are, but I think it is mentioned on his web page.

[Reichert]

Stephen,

I'm not really up to speed on some of the newer audio choices. Dr. Don did not mention anything about adding a "line in" to the DCM.
I think he does some kind of modification to the control head to allow input from different sources. Not sure what they are, but I think it is mentioned on his web page.


It's just something like this (with a 6 foot lead line), to be able to plug in an external audio source: https://www.amazon.com/3-5mm-Stereo-Panel-Mount-Jack/dp/B000ML4A2Q


I haven't yet, but I intend to mount it in the blank space next to the power key.

[dredgeguy]

[LIST]



It's just something like this (with a 6 foot lead line), to be able to plug in an external audio source: https://www.amazon.com/3-5mm-Stereo-Panel-Mount-Jack/dp/B000ML4A2Q


I haven't yet, but I intend to mount it in the blank space next to the power key.

I put the Dr. Don aux input in the center console and have a XM radio hooked up to it. The XM antenna is located under the rear hatch latch, completely out of view and it works great.

[RussMcB]

<snip> The XM antenna is located under the rear hatch latch, completely out of view and it works great.That's a good idea. I put mine under the rear fascia body work (while it was off during the paint job). I like your idea better.

[dredgeguy]

Here is a pic of the XM radio installed using Dr. Don's aux input. Sound is perfect!