Is there any way to test whether an elocker is working or not, if you are going to look at a 4Runner? Short of just pushing the button and making sure you don't hear anything you shouldn't?

 

take it on a dirt road. put it in 4lo. press the magical button, and wait for the RR DIFF LOCK to stop blinking and stay on. make a slow turn...you should feel/hear the rear fighting for traction, or breaking loose of traction. dont forget to turn it off and out of 4lo once youve established alls good in the hood...