service 4 wheel drive light

Discussion in 'GM Powertrain' started by wmc3, Apr 10, 2014.

  1. wmc3

    wmc3 New Member

    I have a 2008 Silverado, 5.3, 4WD (obviously) and the service 4WD light came on. I changed the actuator, the problem "seemed" to go away. It was gone for 3 weeks. Went out today and the light is on again. But this time, it is stuck in 4 low. I tried shutting off the truck, waited and restarted it, still on. Unplugged the actuator, replugged it in, to make sure the plug was on completely and locked on. All good there, no corrosion on the contacts, any ideas???
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I have seen this issue caused by a few different things. first, the encoder motor that shift the t-case could be bad. Second, the dash switch itself. And third: I was at a dealer getting some warranty work done and a guy with a 2009 4x4 was there with the same issue. They told him that the BCM needed reflashed. So, he tried it. Drove out and came back 10 minutes later, it had shifted into 4 low again, at this point they blamed it on the t-case and told him that it needed replaced.

    So, I guess that I would start by checking out the dash switch, they are know to have some bad solder joints in them. Then I would move onto checking out the encoder motor.
  3. wmc3

    wmc3 New Member

    I will look into that tomorrow after my first pot of coffee!!

    - - - Updated - - -

    UPDATE>>>> I replaced the dash switch, got it out of 4 low, and now it is in "Auto". and stuck there. I can't get it to go back to 4 WD, or 2
    WD.......time for a beer.... Still up for an suggestions....
  4. GM Customer Service

    GM Customer Service Epic Member 5+ Years 500 Posts

    Hello wmc3,

    As a customer service representative, I'm not able to provide much in the way of do-it-yourself information, so I'm glad to see forum members are beginning to step in with feedback. If you have any lingering concerns please contact me via private message.

    Jennifer T.
    GM Customer Care

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