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?