My truck is stuck in 4low will not engage?

I don't know who you are talking about, but this sounds like the transfer case actuator, or the front differential actuator is not working. Here is the location so you can replace it. I would see if you could hear the actuators working in each location when you use the 4wd switch. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.

I would remove the transfer case and front differential actuators to see if they move when the system is operated, if so, you could have a broken retraction or engagement spring. Check out the images (below).