I'm replacing the stock stereo in my 2006 Chevy Colorado. All of the diagrams I've seen online show that A1-A7 are unused example but A1 and A2 have a similar, smaller wire (see picture).enter image description here

The adapter that came with my new stereo has four wires for power, IGN+, REM+, B+, and GND-. I don't see where to put these two purple wires from A1 and A2.

New stereo diagram. [![enter image description here][3]][3]

Speaker wiring:

[3]: https://i.stack.imgur.com/hiD7l.jpgenter image description hereenter image description here!

  • Welcome to Motor Vehicle Maintenance & Repair! Jun 11, 2020 at 20:57
  • After reconnecting the original adapter, I connected all of the speaker wires from the new adapter to the old adapter. I then connected to yellow wire to the battery (orange wire), and the red wire to one of the LAN serial networks (purple wires). Truck would not start. Disconnected from LAN connection, truck starts, but no power to stereo. If I connect to either of the purple wires for the LAN while the truck is running, then the dash shuts down.
    – evv_gis
    Jun 11, 2020 at 23:37
  • Alright, I think the issue is the two purple wires will not work either or together as the accessory connection. I need to run a wire from the ignition switch harness (black wire) to the stereo wiring and connect to my red wire on my power harness.
    – evv_gis
    Jun 12, 2020 at 3:03
  • Still no luck. Ran a wire the black wire coming out of the ignition switch harness, connected to the IGN+, still nothing.
    – evv_gis
    Jun 12, 2020 at 12:57

3 Answers 3


The two purple wires usually make up the pair for the right rear speakers. Here's the usual breakout for the wiring:


  • Constant 12V / Memory Keep Alive: Yellow
  • Accessory: Red
  • Dimmer/illumination: Orange w/white stripe


  • Ground: black


  • Right front speaker(+): Gray
  • Right front speaker(-): Gray w/black stripe
  • Left front speaker(+): White
  • Left front speaker(-): White w/black stripe
  • Right rear speaker(+): Purple
  • Right rear speaker(-): Purple w/black stripe
  • Left rear speaker(+): Green
  • Left rear speaker(-): Green w/black stripe


  • Antenna: Blue
  • Amplifier remote turn on: Blue w/white stripe

Those seem to match up very well with your adapter.

  • Thanks. The two purple wires are stock, not part of the aftermarket stereo. Googling is showing they are possibly a LAN serial network line (???). See chevyforum.org/chevy-forums/archive/index.php/t-9136.html. I'll add more photos.
    – evv_gis
    Jun 11, 2020 at 21:05
  • @evv_gis - The purple wires should still align with the RR ... you've got four pairs. I'm not sure why you cut the wires to the vehicle. Most adapters are made to attach the aftermarket wires which come out of the head unit, then plug directly into the stock wiring connectors which were pulled out of the OEM head unit. Jun 11, 2020 at 21:22
  • Because I'm an idiot... But I've reconnected the original adapter, took out the clamps and I see how to put the new adapters on. But the purple wires still don't have a home. All of the speakers are accounted for, these remaining two purple wires are part of the power supply.
    – evv_gis
    Jun 11, 2020 at 22:45

What you have there is part of a "Harness interface". It's for aftermarket stereos for newer vehicles that use a "data bus system" or a instead of a red ignition switch (acc) wire. You're missing the door chime part to complete the set. Without it idk how you're gonna bypass or get it to work. I found your post, albeit almost a year later, when I went to install a different stereo in my truck, 2006 Silverado 1500, and upon taking the old deck out I pulled out a scosche door chime wired in the harness lol. I was like wtf is this?!? At any rate, the pic I have here basically has the red on the door chime wired to the red on the aftermarket harness, the 2 purples go to the 1 purple on the chime (there must be some kind of relay/return signal) and the ground goes to both factory & stereo grounds, then the yellow also goes to both yellows. enter image description here

  • Thanks - I ended up nutting off the serial lines and ran a wire from the steering column to get power. No door chime, but the stereo works without a problem.
    – evv_gis
    Mar 14, 2021 at 19:24

Here is a diagram I found for the 06 Colorado 4 or 5 cylinder engine

enter image description here

  • Thanks, I think I'm good on the speaker wiring. It's just the power harness giving me trouble.
    – evv_gis
    Jun 12, 2020 at 13:04

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