How to test the QNBBM Balancer is working or not?

Some customers are not sure if the balancers are working or not.

On one hand ,if the balancers have led  light, you can see they are normal or not.

when two lights are red, it means the balancer is damaged by too big balance current or short curcuit. 

On the other hand, if the lights are off, how to verify if the balancers are fine or not? here is instructions:

Step 1 : disconnect balance wires (the green and blue wires) , 

make sure the battery is connected to the balancer.Also make sure the battery capacity is over 50% capacity left.

Step 2, use multi-meter (choose "AC" volt) ,red probe and black probe put into the white connector as the photo below:

if the meter shows 0V, it means the balancer is defective. 

if the meter doesn't show  similar voltage to the real volt of the battery, it means the balancer is no problem. 

Suppose if the meter shows above  a voltage,but the two led lights are both dark(all the wires are properly connected)

 it means the balancer is good but the lights are damaged.