4WD Problem - 4L will not engage and same with rear diff. lock

I'm new to the forum with a 2012 Tacoma with a manual transmission. I cant get 4L to engage. It will blink and beep but wont switch into gear. 4H is fine and switches into gear. I followed the instructions in the manual exactly. Rear diff lock wont engage either because of this. Is the transfer case the problem? New fluid/oil in both the transfer case and rear diff. Haven't change the front yet. Thanks for reading this.

 

You didn't say if you have a manual or auto trans.

To get my manual trans Tacoma into 4L I must push the clutch to the floor harder than to start it. If I don't push it hard enough I have to turn it back to 4H, push harder, then turn it to 4L again.