4wd will not engage, no message?

The 4WD switch blinking about 5 times and then stopping usually means the TCCM tried to make the shift, did not see the expected feedback, and aborted the command. I have seen the front axle actuator go bad and cause this problem as well so you might want to remove it and then work the system to see if the actuator works. Also, there are three fuses that run the system so please make sure those are good as well. Here are the fuse and locations along with the system wiring diagrams so you can see how the system works. Check out the images (below). Please upload a short video in your response, so I can see what's going on.

I have removed the front axle actuator, and plugged it. Should it retract or extend when I try to select 4WD? I see no movement in or out.
I had checked the fuses before I asked the first question, they are all good.

Well Sir, Because I saw no movement, I bought and installed a new front axle actuator. Did not fix the problem. I even went from ground and got a test light to light up on one of the pins of the harness that feeds it. Sorry

Hmm, I have seen the switch cause this issue as well FYI, but we should run a CAN scan to see if any codes are stored.

CAN SCAN - https://youtu.be/u-4syLc-ifQ

Please go over this guide and get back to us.

Thank You for your help. I found that the harness to the front axle actuator has 2 wires that are not conducting. That harness is not available new, so I will be searching for one from a junkyard. If that doesnt fix it, I have an appt at a shop to at least do the CAN scan on the 31st. Again Thank You!

Good work, the CAN should show a code for what the problem is exactly. Please let me know I am interested.

Hello Ken, I'm giving you an update. The shop didn't do the "CAN
SCAN" until Thur April 2. They found nothing wrong with the wiring, but said the Control Module was intermittent, because they could get into 4WH, with their
scan tool, but it wouldn't come out. They have ordered the Control Module and said they would call after they put it in. Apparently it hasn't come in, or they are too busy to get to it. My thoughts are that the original problem is/was the control module. The new Control Module needs a software reset, too.
Thank You, Tim
Turns out I should have taken it to them in the first place. Now it's costing me close to double because electrical parts are not returnable.

Yep, it can turn out this way, electrical problems can be difficult, let me know if the module fixes it.

Yes, the module fixed it. Turns out he put a used one in. His whole bill came to $500. Charged $200 to program it. I wonder if I found one in a junkyard for the 2500HD if it would have worked without programming it. Well, it's working, so upward and onward. Thank You for your help.

Glad you could get it fixed, thanks for letting us know. Please use 2CarPros anytime we are here to help.