98 Jimmy 4x4 switch

Discussion in 'GM Powertrain' started by otis24, Feb 28, 2009.

  1. otis24

    otis24 Member

    My 4x4 will not engage in 4 Low, but it will engage in 4 Hi. In the owners manual, it states to put the vehicle in neutral, switch to 4Lo. It the lights flash, shift into park while lights are flashing and wait for it to switch into 4Lo. It states that if the Jimmy does this, you need to have the switch adjusted.

    My Jimmy has these symptoms. However, when you select 4Lo, both the 4Hi and 4Lo buttons light up. Is there an adjustment in the switch, does the switch need to be replaced, or is there another problem?

    In addition, I have the same size tires on both front and back, but they are two different brands. I was told that this could affect it as well. Any thoughts?
  2. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    4wd operate by push button or lever?

    AS for different make tires, I've had trouble with that scenario on previous part time 4wd vehicles. It depends on the exact diameter of the tires, but different manufacturers can generate a little bit different overall diameter for their tires. If that difference is great enough, it can cause drivetrain noises, binding, hard to disengage 4wd, and other symptoms. If you only use the 4wd when traction is poor (as you should), and you don't have any symptoms, you're probably ok. If you experience problems using the 4wd, then you might look into the mismatched tires as a possible cause. Personally, this is one reason I find it so much more important on a 4wd vehicle to rotate the tires: to try to avoid a scenario where I want to only replace two tires at a time.
  3. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Older 4wd's (I'm guessing yours is newer because of the push button) used to suffer from issues like this, the solution was to roll forward and backward a little to let the gears mesh better.

    Like Mrshorty posted if the tires are to great a difference in size this could be an issue.

    Something auto manufacturers fail to recognize is that sometimes you can have two tires the same listed size and manufacturer and have them be as much as 1.5" different. This happens a lot on larger off-road tires (sometimes even more than 1.5"). The problem comes from the original tire castings, they change sizes with the repeated heating and cooling cycles because of expansion and contraction rates of the casting metal.
  4. otis24

    otis24 Member

    Here's whats going on now. If you put it in 4WD (Hi or Lo) while in neutral, the lights flash then kick to 2WD.

    When the vehicle is in park and you push the 4x4 buttons, nothing happens. I'll measure the tires and see if that is a possibility. How would one diagnose if it is a switch problem?
  5. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    This sounds like a switch or sensor.

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