power lock problem?

[milin1609]

Hi , I can not lock my 2000 chevy express v8 5.7L using power lock switch.I can open it but can't lock. The switch on passenger side works fine. I also can use remote to lock and unlock successfully. but can't lock using the driver side switch.Any idea, what's wrong?

[Bob86ZZ4]

Can you get the switch out of the driver's door and check the terminals with a test light while you activate the switch to see if it's working correctly?