Tow/haul stuck ON....2000 Chevy Z-71

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by sbeduckman, May 16, 2010.

  1. sbeduckman

    sbeduckman New Member

    Last week, my 2000 Chevy Silverado Z-71 began shifting itself into tow/haul mode. It would come and go, but the button was never the reason why it would turn off or on. The on and off routine didn't last long however, for the last several days, it has been stuck in the ON position. The dash light is lit, and the transmission is engaged in tow/haul mode. What can I do to get it back off? I'm not sure if there is a risk of damage to the tranny or not at this point, but I doubt if it's doing the truck any favors. If nothing else, I imagine my gas milage is suffering. Any ideas you guys have are greatly appreciated. Thanks in advance!
  2. rmck490

    rmck490 New Member

    I've heard the wires on the tow/haul can sometimes become pinched in the steering column and are either cut or partially cut exposing the wires through the insulation. It appears you have an intermittent short to ground in the wiring or a bad two/haul switch in the shift lever.

    The tow/haul switch is a monentary switch that sends a ground signal to the body control module (BCM) when the button is pressed each time (on then off with each press). The BCM tells the powertrain control module (PCM) whether it is on or off which then commands the mode of the transmission.

    Yes, your gas mileage will suffer but it's okay to drive.

    If you are a do-it-yourself type, find the Lt Blue wire in the column that comes from the button and trace it to the BCM looking for a break in the insulating cover and repair it. Most likely this will be in the column somewhere and probably near the moving parts of the shift lever where chaffing is possible. If that doesn't work for you, take it to a mechanic to diagnose the problem.

    Hope this helps you.

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