Hello I created a bench harness and some car radios when I connect 12v and ground to them, they can be powered up.  Other types of radios on the other hand, they won't power up.  There must be some other wire that needs to be connected to the radio?  I can't figure out which after reviewing AllData connector views.  I admit I don't understand clearly the function of each wire based on how it is described in the schematic.  Perhaps some signal needs to be transmitted over GMLAN bus.  Who knows!!  I am wondering if anyone has any idea to help me power up the stubborn radios, such as 2015 GMC Acadia.  Thank you.

Do you have GM service information for the radio connector pins for that radio?  

I was only able to fully power on my navi650 after adding a bcm to the bench harness..

Most car radios have permanent power (12V_ACC red wire) - for storing settings, clock and "quick-start", and ignition switched power (12V_IGN yellow wire) - for powering up the unit after user have turned on the engine.

Physically, power for both can (and probably will) be supplied from permanent ACC wire, but unit still does need a signal from Ignition switch to trigger it to boot properly.
This "signal" can be a switched +12V line, as I've mentioned above, or a CAN-bus message. If it has a "wake-up call" by CAN-bus - usually it means that you also require a BCM module, which usually is responsible for such things in the car.

Car radios are pretty straight forward, so if you have a wiring diagram - it will be easy to figure things out!

complete the schematics,, power, ground, serial data and most

 

1 minute ago, LLCasaol said:

complete the schematics,, power, ground, serial data,,,,,

Ive sent you a PM with a video tutorial on how to build a working bench harness that will boot the radio via can-bus message from the BCM

Thank you very much

3 hours ago, Troy said:

Do you have GM service information for the radio connector pins for that radio?  

Yes I do, it has 4 connections in back (also a usb and antenna)

ALLDATA Repair.pdf ALLDATA Repair2.pdf ALLDATA Repair3.pdf ALLDATA Repair4.pdf

6 hours ago, med458 said:

Yes I do, it has 4 connections in back (also a usb and antenna)

ALLDATA Repair.pdf 135.6 kB · 2 downloads ALLDATA Repair2.pdf 136.05 kB · 1 download ALLDATA Repair3.pdf 130.05 kB · 1 download ALLDATA Repair4.pdf 114.54 kB · 1 download

 

Check this PDF edit.

Battery power positive, negative and the serial data wire PIN 13 circuit 5660 should connect to the BCM. Check if the BCM PIN schematics have that PIN 13, circuit 5660.

ALLDATA Repair.pdf

Radio Pin

 

On 2/28/2023 at 7:11 AM, pistnbroke said:

Ive sent you a PM with a video tutorial on how to build a working bench harness that will boot the radio via can-bus message from the BCM

It will take me time to get a compatible BCM in my possession.  In the meantime let me ask, must the BCM VIN match the radio or will any BCM I can get from a salvage yard from that type of car work for the purpose of a bench harness?  Thank you again.

14 minutes ago, med458 said:

It will take me time to get a compatible BCM in my possession.  In the meantime let me ask, must the BCM VIN match the radio or will any BCM I can get from a salvage yard from that type of car work for the purpose of a bench harness?  Thank you again.

No problem, no the vin doesn't need to match but obviously the radio will theft lock if they are different. either unlock the radio or as bcm's are configurable via xml it's also not a problem to change the vin in that to match the radio instead..

You may also find you need a signal to trigger the display to turn on, for my loom I used the 7066 circuit ( on your radio X1 pin 6 ) to do that and all works great..

On 3/1/2023 at 1:13 PM, pistnbroke said:

You may also find you need a signal to trigger the display to turn on, for my loom I used the 7066 circuit ( on your radio X1 pin 6 ) to do that and all works great..

Thank you for your reply may I please seek clarification, first you mention the 7066 circuit, I am curious about the type of "signal" needed.  Is that 12v?  Or some data?  I look at the information bus map and it looks like pin 6 connects to the car antenna.

3 hours ago, med458 said:

Thank you for your reply may I please seek clarification, first you mention the 7066 circuit, I am curious about the type of "signal" needed.  Is that 12v?  Or some data?  I look at the information bus map and it looks like pin 6 connects to the car antenna.

Sure, I've not put a meter on it as yet I used that circuit because the schematics show it like that for my radio and external display.. Sorry should of said if your radio and display are 1 unit ignore this part..👍