4WD Actuator or Diff actuator not working

Morning ALL, I'm new to posting like this on a forum. I have already found some great posting of much needed info for my out of order 4wd on my 2008 Sequoia. I just wanted to introduce myself. My family of six have had our Sequoia for 8 years now and it has been very reliable, about a year ago the 4wd stopped functioning correctly and has even been stuck in 4wd for a short distance. I've come to narrow down the issue and how to possibly repair it, Lord willing w/o removing/replacing the transfer case. Thanks

 

Stopped functioning is kind of a general explanation. Does the Sequoia normally shift into 4x4 but not indicate a completed action? What are your electronic indications? Does it not shift out of 4x4? Are there disagreement lights flashing?
I went through this with a 4runner and it ended up being a transfer case position switch failure. $35 for a new switch self installed. Of course I paid $90 because I bought the switch at Toyota, should have shopped around.