Won’t shift into four-wheel-drive when running

Hi new to the group I have a 2007 Tacoma. It is V6 automatic four-wheel-drive. Four-wheel-drive was working fine then today it quit. I found that it will not shift into four-wheel-drive while the truck is running. If you move the selector switch to four-wheel-drive nothing lights up on the dashboard and the truck does not engage. If you leave the selector switch in four-wheel-drive position and turn the truck off and start the truck back up it will go into four-wheel-drive fine. You can take it out of four-wheel-drive while it is running but it will not go back in. Again leave the selector switch in four-wheel-drive position turn the truck off start it back up goes in fine. Anyone ever had this happen or have any idea where to start looking? Thanks in advance

 

My advice is diagnose the right part, the first time.
Yes, it’s a bit time consuming.
But it will save you a lot of money and time later.

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

My guess is that it’s the actuator on the front differential.
That’s a GUESS, DO NOT GUESS.

 

So you don't even get a flashing 4wd light when you try to engage it with the engine running?

 

That’s right no light when engine is running. Unless I shut it off then put it in four-wheel-drive and start it up. Then the light will come on.

 

Bust out the meter and take some readings. Nothing more we can tell you to help besides that at this point.

 

Sounds like a possible switch or module problem but you will need to do some testing of voltages at the module to see what's going on, the link that @TnShooter posted above has all the expected voltages in each mode.

 

Figured it out guys. I disconnected the battery and hooked it back up and it must have reset itself. It’s working fine now. Thanks for the help.

 

i am hopeful I am wrong but I’ve never seen that fix any 4wd related issues.

 

No me neither. But also had the same issue with the cruise control. And disconnected the battery and re-hooking it up seem to solve the problem