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Decent in-cab reverse circuit location for 99-06 OBS?

Discussion in 'GM Electrical Tech' started by SurrealOne, Oct 22, 2011.

  1. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    I'm installing a new head unit and backup camera and am looking for a decent, in-cab reverse circuit location to tap into -- specifically so the head unit knows to switch to the backup camera when the vehicle is placed in reverse. I'm desperately trying to avoid going through the firewall and into the under-hood fuse block (where I know I can tap the reverse circuit), as it's a royal pain. There's got to be one...

    This is in a 2004 GMC Sierra 4x4. Any pointers would be appreciated.
  2. sstoner911

    sstoner911 New Member 1000 Posts

    There should be a DK blue wire at the BCM that is a reverse circuit. I pretty sure your year has a BCM which is left of the steering column generally
  3. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Looks like the BCM is directly under the steering column. I have two dark blue wires going into it. :(
  4. McMahan

    McMahan New Member

    X2 just get yourself a test light and put it on one of the dark blue wires and put it in revers and if it lights up that will be the wire you want and if it don't light up then it's the other one
  5. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    I'm always wary of the potential to short things with that approach. Also, it'll be a LOT of work to do that, as I have the seats out of the vehicle right now (sound deadening work, installation of stealth sub under center console, etc.) and, well, I'd have to put them back in (so I don't end up with the system telling me to service the air bag) and reconnect the battery to do it.

    Speaking of that, is there any way to avoid that (reinsertion of seats prior to connecting battery) or to simply clear the service air bag warning if it surfaces? It'd make life so much simpler if I had battery power for things I"m working on... with the seats still out.
  6. sstoner911

    sstoner911 New Member 1000 Posts

    Not that I know of. But as mentioned by McMahan a test light should be the ticket to see which wire you want.
  7. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    For future reference, on a 2004 GMC Sierra 1500 (non-HD) the reverse wire is the LIGHT GREEN wire connected to the black plug in the BCM.


    P.S. Dark Blue is apparently for the 07's...
    Last edited: Oct 24, 2011

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