ld4t3

I have a 2001 Sierra. I know this is a chevy group, but it is the same identical problematic truck as the Silverado. It's doing the same thing as hundreds of other posts I've went through for countless hours where the service 4wd message is on with the exception of the push button selector switch acting differently. Unlike most other complaints I've seen where the lights fail to come on or flash when trying to engage 4wd and result as an incomplete shift returning to 2wd, every single indicator light on my selector switch is lit up and stays lit up no matter what I push. Every once in a while the message 4wd light and selector switch go back to normal and everything works perfectly, and I mean every step of the process. Please don't suggest that it's the switch, as I've been through three of them. I did reflow all of the solder joints in the original which helped for about two hours. After swapping the other two with no change I tested the ohms in all three and the numbers were identical. The majority of the time I start it the selector switch is lit up like a Christmas tree along with the service 4wd message. I've become so used to it that I don't realize they're not lit because my truck will have it's full power restored. I forgot to mention that when everything is lit up, it acts as if it's in 3rd gear the whole time. It starts off very sluggish from a stoplight and will not downshift no matter how hard or how many times I push the pedal to the floor. When I get a few hundred feet down the road it almost acts as if it's running out of gas then runs like it's in full time third gear like I previously stated. If anyone has a worthwhile suggestion I will be ecstatic to listen to your input, thoughts, and /or suggestions. I haven't had a chance to see if it will produce any codes and my scanner doesn't arrive for two more days, but any info in the meantime would probably help my impatience to finally resolve this. Thank you in advance for your input.