CDM mod 88-94 GM trucks

Disecting a GM Delco electronics factory radio to add a aux input. Here I have found pins 11- audio left 12- audio common 13- audio right 14- audio right on the top of the CDM box are unused other wise and are inputs. On the bottom of the CDM is the slave connector for the tape deck. Pins 16-14volts 13- Tape ON 11 Audio common 10-Audio right 9- Audio left are from the tape deck. Pins 16 and 13 shorted together jump the CDM into aux input mode as if there was a tape in the machine without engagement of the actual tape deck.

[@89lxman]

Thank you for this awesome video... I have been sharing it ALOT on the FACEBOOK groups to AUX input a CDM!!

[@ajf1006]

This is the best video on KZbin. I've searched and search how to do this, I'm going to be adding Bluetooth Module as opposed to the audio jacks

[@DRNEGOLICIS]

I have one attached to a 12-5volt reg that uses the radios power. Every time the radio comes on, phone comnects and starts playing my music

[@corydurand3158]

Awesome job, you saved me time and money. Thank you for your work.

[@Elmobeaver]

What you are doing here is right up my alley. Thanks so much for sharing. I will subscribe to your channel. Also, any idea on how I can obtain a wiring diagram for that particular setup?

[@DRNEGOLICIS]

Check my next video

[@mikewolfe789]

Do you know where the single white wire connects of of the equalizer/ tape deck the radio works but no lights to the cd player?

[@CORVAIRWILD]

Wow!!!

[@DRNEGOLICIS]

Hay man good to see you in the comments. I’ve been a long time follower since I was a kid. Honor to have one of my child hood influences show up here :)

[@kevindavis4709]

The reason people change them out cause they’re not cheep if you get 3 peace’s it’ll nearly cost. 500$ but for a used radio unless you go to a junkyard get one less than 50$. That’s why GM stopped making these radios a 3 peace. It’ll be nice too find one new on eBay with some people like myself on fixed income you can’t afford a 400$ mistake on a used Delco radio that is a 3 peach. I have a 2001 Silverado I bought a new CD Delco radio under 140$. Plus you don’t gotta reset your stations each time the battery is unplugged

[@icyscenic6783]

im curious if id be able to have the control head still operable and have an after market head unit installed into where the tape player is and have them both functionable??

[@DRNEGOLICIS]

Not sure why you would want two radios ….. but you don’t have to have the cassette player plugged in for the stock cdm to operate, if you have a EQ you’ll need the cassette deck connected to set your EQ before you disconnect it’ll remember the setting as long as the batt is connected

[@adrianmtz5016]

Hello, awesome vid... any idea which wires I can hot wire to simply have my equalizer screen turn... don't really need anything else

[@noblsht]

I do have one of the units that I purchase which has the external wire that is soldered inside ,one of the two outputs has failed I only have sound coming out of one speaker and the other is intermittent but once I take it out of the truck and open it up I will be able to see where the two wires were soldered I am considering trying your system also with the original cassette plug because the cassette is no longer able to be purchased from General Motors and who wants to use a cassette any longer anyway but I will get back once I open it up and see where the soldered connections are

[@kylewhittington8384]

I have a question as to where the single white wire goes to, the wire is separate from the control head wiring. It has as little black connector on the end of it. Looks like in the video it is connected to a little batters source.

[@DRNEGOLICIS]

Off the back of the head? Onea serial data for the EQ option

[@joelgonzalez3115]

I plugged in my control head and turned the volume all the way up and it’s low, and reason why?

[@DRNEGOLICIS]

Gets loud at key on then drops down? Not sure but its a failure mode. I haven't actually repaired one yet. I've recapped one once but that's it

[@jacobknuckles9218]

Can you recommend a Bluetooth adapter and how I would wire it instead of the aux?

[@jacobknuckles9218]

I was looking at the millennia milbtrec unit from Crutchfield. But not sure where I would run the 4 wires. There’s a left and right but no common for audio, and then there’s a hot and a ground wire

[@DRNEGOLICIS]

I bought a generic blue tooth board the size of a quarter off amazon and have it wired up to turn off and on with they key. Its just plugged in the aux cord and zip tied under the dash.

[@Mohammed-uz1sn]

​@@DRNEGOLICIShi hi hi hi ????

[@GoodTimeBikes]

What are you using as a power source while it’s on your bench? Also, thank you for this awesome video! I have a 93 and I believe the CDM stopped working. Once I get that sorted out I’d like to install switch for Bluetooth.

[@DRNEGOLICIS]

Astron 10 or 20 amp I think

[@GoodTimeBikes]

@@DRNEGOLICIS thank you!

[@therogalofamilyfarm2045]

Have you ever had one of the 88 to 99 radios stay at 100? I'm having this problem with my 93. It won't change from 1 and nothing works no music nothing except the clock saying 100

[@letaloudone]

Mine doing same thing. It's the cdm crapped out.

[@DRNEGOLICIS]

The clock should be built in the control head. I was having issues with buttons not working at all, a quick test with a known good control head proved the CDM to be in working order. I took apart the failed control head and found the pins had tarnished, cleaned reassembled and re-installed, unit works Ok now. Oh and also when the clock did decide to work. It would give weird times like 1:73

[@noblsht]

Yes it is the main brain box I would say pretty much controls everything the amplifier CDM box

[@mrpanda2655]

When i turn on my radio all i get is static on FM or AM. Any idea on what it could be?

[@DRNEGOLICIS]

Use a wire for an antenna and see if it works. Sometimes the antenna connection under the hood fails. If that don’t work then you have a PLL VFO issue with the actual CDM I don’t have a fix for that yet

[@mrpanda2655]

@@DRNEGOLICIS I just replaced my dashboard and noticed that the speakers are disintegrated. Would that have any effect causing the static? Only one speaker was working in the truck and I see why now

[@mrpanda2655]

@@DRNEGOLICISalso did you ever find a way to wire an aux to the radio? And if so can I send mine in

[@mrpanda2655]

@@DRNEGOLICISthe antenna is fine. I hooked up a cdm off an 80s model and it worked for a split second then stopped working. Could it be the caps?

[@DJAlup]

Any idea how to fix the CDM when they fail and go to 98.1 and 1:00?

[@DRNEGOLICIS]

Not sure yet, if I can find pcb diagrams I would. Cant see as well as I once could so I can't build or repair stuff like this as I once could

[@diegopalacios4986]

Ok , when and where are you selling a kit so i can just plug and play !!

[@DRNEGOLICIS]

Hmm probably should.