Locker- RR diff lock light

[edman111]

I have had a 2004 tacoma 4x4 (automatic) for about 2 months. It has just under 30k miles. I was cruising the interstate 2wd and the locker light started fading in and out. The button has always been on Normal. I stopped and pushed the button in and out a few times and put it in 4wd and back in 2wd. Then tried the highway again. Its faded on very dimly then went out for the rest of the trip.
Could it just be a sensor problem or???

Thanks in advance.

[Hoodlum]

Is the locker working or not?