4wd will not engage

What year is the suburban? does it work if you lock it into 4 wheel drive? how bout in 4 low? More details make it a lot easier to troubleshoot.

Does the light on the button blink when you push it?

Yes 1999 k2500 2 auto 4hi 4lo will stay lit on 2 4hi and auto when you push 4 lo it blinks but goes back to 4 hi. Actual though truck is in 2 wheel no matter what

I think the transmission is supposed to be in neutral before you shift into 4lo. I had an '01 Blazer with the same drivetrain as my 99 Suburban and that was the case.

It is a 1997 Chevrolet Suburban. The light will blink when you try to put it into 4 wheel hi but it does not engage.