4wd problems 2015

So i was driving normally yesterday and my 4wd icon starts flashing on the dash. I pull into a gas station to switch over to 4h and back to see if it fixes it and 4 low popped up on the dash. Ive tried everything i can think of. Even left neg off battery for the night and nothing. The dealership said to fix it i have to replace the whole transfer case which i know is bs. Pretty sure its the tc actuator or the add. Is there anything i can do before deciding to replace those or what? First problem ive had in 7 years lol

 

Maybe corrosion, take apart and clean actuator

 

You may want to check the vent hoses on the actuators, if they get cracked or disconnected moisture and dirt can get inside and mess up the contacts.
They can be taken apart and cleaned, sometimes that will fix them and sometimes not.
I also have alot of information about the 4wd system compiled in the thread below.
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/