First the passenger window became unreliable. I brought it to a body shop. It worked properly for him. He tested the motor. Worked fine. He replaced the switches on both the driver and passenger side. Didn't solve the problem. I told him to replace the motor. Didn't solve the problem. The problem spread to the drivers side window. Now both windows work most, but not all the time. Brought it to the Chevy dealer. They don't know whats wrong. Anyone else have this problem?

 

Ive had this problem since I bought my current mc. Sometimes they just dont work the first time I press the switch. I can hold it down as long as I want, still wont work. Always works on the second try tho.

Tested and replaced the same as you. Same problem. Guess Ill replace the doors if they ever quit working lol.

 

There's most likely a problem in the wiring somewhere, you'd just need to trace all of it to find it.