OnStar Unit Location within 2004 GMC Sierra?

Discussion in 'Audio, Video & Gadget Tech' started by SurrealOne, Jan 1, 2012.

  1. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    I'm trying to find a diagram showing where the OnStar unit is hidden as my search for it has yielded no fruit. I strongly suspect it's under the dash behind the air bag as that's one of the few stones I've left unturned ... but I'm hesitent to go poking around, there, without a diagram or some explanation of how that area is put together.

    Can anyone provide some insight?

  2. Enkeiavalanche

    Enkeiavalanche Loving the Outdoors Staff Member 5+ Years ROTM Winner 5000 Posts

    I belive it's behind the glove box or in the dash
  3. redneck70

    redneck70 Rockstar

    The box your thinking of behind the glove box is for the XM radio. I found a post on another site that claims that the OnStar box on a 2004 2500HD Silverado is located behind the dashboard on the passenger side. You have to remove the upper part of the dash to access it and work between it and the firewall. It's the smaller module at the bottom. I've never done it myself and sounds like a tonne of work but if you already have your dash apart that might be a place to look.
  4. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    I pulled the XM radio some time ago. (Wow that thing was massive for what it does.) I've also read the post you referenced but, sadly, it included no photos and its instructions were VERY hard to follow without visual aid. I'll need a diagram before I'm comfortable working around the air bag. If I can't find a diagram I may content myself with pulling the antenna wire for the unit since I know it comes up one of the A-pillars. (If memory serves it comes up the passenger side, but it's been a while since I had the headliner out...)

    I learned that yanking the fuse just disables to voice junk.


    P.S. It's not behind the glove box, Enkie. It's also not behind the radio or behind the instrument cluster or under the driver's side kick plate. If it's in the dash it's gotta be up by the passenger side somewhere.
  5. sstoner911

    sstoner911 Epic Member 5+ Years 1000 Posts

    My Onstar brain is located behind the lower middle dash panel that has the ash tray in it.
  6. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Thanks. Sadly it's in a different location for your NNBS truck than it is on my NBS truck. :(
  7. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Found it. Passenger side -- behind the air bag. It can be (and was, shortly after I found it) disconnected from the glove box. I'll likely post a how-to on this with pictures, this week, such that others with the same body style as me know what to look for and what to disconnect. I'm also going to remove the sucker (without removing the dash; my small hands will likely let me). I got 80% of the way there but had to quit because the temp dropped quickly on me and it became too cold to work outside.


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