4WD system not working

Hello, I have a 2012 Tacoma. The 4wd system has been giving me issues, my 4wd light is on the dash, and my 4Lo is blinking. I am in 2 wheel drive though and I checked by lifting the front end of the truck up and checking that way. When I turn the dial on the dash I don’t hear anything “clicking” or something trying to engage. I have taken apart the transfer case actuator and cleaned that all up and put it back together but still not luck. My next step was to pull the front ADD apart but can’t get the 4 screws to budge and are starting to strip. So before I starting flat sides on the screws to get it apart I wanted to see if I was wasting my time with seeing if it’s the ADD or I need a new transfer case actuator. Thank you.

 

Hey, Is they corrosion on your undercarriage? What state do you live in?

 

This video helped me fix my issue and got my 4x4 to engage. The soldering part is where the main issue was for me.

https://www.youtube.com/watch?v=ZJESG91GbCQ&t=329s

 

Check your limit switch voltages as outlined in the thread below and post your results so we can see what part of the system is causing the problem.
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Not very much corrosion at all, live in the Western side of Nevada in the desert.

 

Thank you, I’ll check chose limit switch voltages when I get back from work (headed out of town for the week).
In the mean time I took apart the transfer case solenoid again. When I put the circular shaped gear back in, I manually rotated it with my hand and could the limit switches going on and going off when I go. When I put the black cover back on I hoped inside and didn’t have any flashing lights. But when using the switch to try and engage 4hi and 4Lo, no luck. Could that mean that it’s not communicating with the front ADD?

 

There's so many possibilities, the gear could be out of time as well.
I always start with the limit switch voltages if there's nothing obvious to see where everything is at and if they are in a plausible position.
If you read through the thread I posted, we have had pretty good success diagnosing the system using this method.

 

Yup....had the same issue you described after my frame replacement. Pulled out both limit switches cleaned them real good with brake clean both in front of and behind the round actuator and reinstalled....no problems since and that was several years ago. I use my 4x4 typically one to twice a month.