Hey welcome to the forum. On the '97s is the switch labeled "2WD 4Auto 4Low"? I know on the '96s it was. If that's the case then you already have 2wd which is the purpose of the Brown wire mod. Although if you just have 4auto 4WD I think there is a mod you can do to make it full 4high 4wd. I don't know how to do that. gijoecam is the expert on that. He'll probably chime in in a little while. If yours is "Auto 4high 4low" then you are a prime canadite for it. The advantages are you can have 2wd which uses less fuel because it's not driving the front wheels in addition to the rear ones. It also lets you do donuts in the snow.
There aren't really any disadvantages because you still have Auto in addition to 2wd. Try searching for "brown wire mod" there are oddles of threads about it.
Here's the main one. That last several pages of this thread are the pertinate ones. Anything talking about the yellow wire don't pay attention to.
Dead Link Removed