how do i test to see if my clutch has failed?
You said in your first post....
washer won't agitate or spin just make humming sound.
The clutch is only used during the spin cycle. The clutch does nothing during the wash cycle when the washer agitates, so I doubt the problem is with your clutch if your washer does not agitate.
If the humming sound is coming from the motor during the wash and spin cycle this would also lead me to believe the lid switch is working.
washer won't agitate or spin just make humming sound. It does fill and drain but will not agitate or spin.
This sure sounds like a classic case of a bad motor coupler, but being you said you check the coupler and it's fine I will be interested in knowing what you end up finding wrong with the washer.