2004 GMC Canyon---4wd not working

tonbec6972

I have a 2004 gmc canyon 3.5 liter 4wd. I'm stumped because my 4wd. isn't working. i installed a new axle axuator,
selector switch, checked all the fuses and they are good. grounds are good. The 2 high on my selector switch lights up but when i push 4h or 4l nothing. there is no sound of it clicking or going into 4wd .there is no warning lights on my dash either. If i'm missing something please tell me, i ordered a chiltons manual and what a waste of my time and money.

Mr_Shiftright

Here's a VIDEO that gives you an idea of how to approach this problem. As you will see, that aside from some manual testing on a lift, what you'll need is a scan tool monitoring the data stream in real time to see what is, or is not, working in the 4WD system.

What the technician did in this video is step-by-step isolation of what IS working, to arrive at what ISN'T working.