NEED HELP 05 TB with no switched power to radio

Jerry Jastram

Original poster
Member
Oct 25, 2015
17
USA
My 2005 TB has a radio problem. I pulled the radio and I have 12v on the orange wire that is hot all the time. But when I turn the key to ON or RUN I do not get power on the switched yellow power wire. I replace the ignition switch because it is easy to do and are problematic, and that didn't help. I have a Haynes Repair Manual and I can't find the yellow wire any place in the schematics. The fuses in both boxes for ignition and radio are good, unless I am missing one not shown in the diagrams. Any suggestion on where to look next would be greatly appreciated.
 

Blckshdw

Moderator
Nov 20, 2011
10,665
Tampa Bay Area, FL
Is this a stock radio, or an aftermarket one?
 

Blckshdw

Moderator
Nov 20, 2011
10,665
Tampa Bay Area, FL
I never had the original radio in my truck, but I believe the "turn on" signal is sent through the class II data bus, not your traditional ignition switch signal. That's one of the big reasons we have to buy adapters when we install aftermarket units.

This yellow wire you have, since it's not in the manual/schematics, can you trace back to it's origin?
 
  • Like
Reactions: mrrsm

Jerry Jastram

Original poster
Member
Oct 25, 2015
17
USA
I will try that tomorrow since I still have the dash bezel off. I am about ready to send the radio in to an online repair center. The radio works except for the clock/station display is not lighting up. It had no sound from the driver's door speaker so I replaced both front door speakers. That fixed that problem and it never sounded this good even when it was brand new.
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,639
Tampa Bay Area
As per @Blckshdw ...

After you solve the primary problem of establishing that the Radio IS receiving 12 Volts DC and that you have a Good Solid Ground:

If you look at at the Diagram of the Class 2 Network Wiring for the entire Vehicle... observe the very lower right hand section of the schematic to follow the ORG (Orange Wire) Circuit # 1044 connection leading from the Radio back to the centralized meeting point for ALL Class 2 Network Connections Point in the middle of the Diagram. The Class 2 Network is a "Single Wire" type of Network System that operates from 0-7 Volts DC ...with the ordinary "PWM" Pulse Width Modulation communications happening between 0-5 Volts DC:

GMCLASS2NETWORK.jpeg

These next attached images are of the PCM Printouts for the Three Colored Connectors attached at the PCM (White-Blue-Nat), with explanations of there Binary Color Coding and each wire Pin-Out to the PCM from everywhere else in the system. It may be necessary to examine the harness connectors adjacent the PCM related to possible broken wire(s) controlling the Radio. Download and use those Multiple Wiring Diagrams to know where to look for the Wires Controlling the Radio ...and what Color (Single or Combination) to look for to search for any Damaged or Broken Wire to Pinout Connections:

PCMC1.pngPCMC2B.pngPCMC3ACCPEDL.jpegPCMC2A.pngPCMC2C3.png
 

Jerry Jastram

Original poster
Member
Oct 25, 2015
17
USA
As per @Blckshdw ...

After you solve the primary problem of establishing that the Radio IS receiving 12 Volts DC and that you have a Good Solid Ground:

If you look at at the Diagram of the Class 2 Network Wiring for the entire Vehicle... observe the very lower right hand section of the schematic to follow the ORG (Orange Wire) Circuit # 1044 connection leading from the Radio back to the centralized meeting point for ALL Class 2 Network Connections Point in the middle of the Diagram. The Class 2 Network is a "Single Wire" type of Network System that operates from 0-7 Volts DC ...with the ordinary "PWM" Pulse Width Modulation communications happening between 0-5 Volts DC:

View attachment 90043

These next attached images are of the PCM Printouts for the Three Colored Connectors attached at the PCM (White-Blue-Nat), with explanations of there Binary Color Coding and each wire Pin-Out to the PCM from everywhere else in the system. It may be necessary to examine the harness connectors adjacent the PCM related to possible broken wire(s) controlling the Radio. Download and use those Multiple Wiring Diagrams to know where to look for the Wires Controlling the Radio ...and what Color (Single or Combination) to look for to search for any Damaged or Broken Wire to Pinout Connections:

View attachment 90044View attachment 90045View attachment 90046View attachment 90047View attachment 90048
Thank you for this info, it is exactly what I was missing.
 
  • Like
Reactions: mrrsm

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,639
Tampa Bay Area
Since you are a "Professional Electron Chaser"... I knew that you'd appreciate what these can mean more than most of us. I hope you get to sort things out. ;>)
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,639
Tampa Bay Area
Incidentally... for THIS particular problem...and everything else that might need Diagnostics and Repairs... Visit @Mooseman 's Epic , FREE "Need Manuals? Get Them HERE..." Thread and follow his instructions to Download a Complete GM OEM Digital Service Manual. The Diagnostic TREE in there for the Radio Issues could prove to be even more useful to help with your present situation:

https://gmtnation.com/forums/threads/need-service-manuals-get-them-here.361/
 

Forum Statistics

Threads
23,272
Posts
637,479
Members
18,472
Latest member
MissCrutcher

Members Online