It sounds like the module is the problem. It's odd that when you provide a ground (via your test light) the windows work. I wouldn't think that three would go bad at the same time so this is a bit confusing.
Go to the switches and check to see if you have continuity through the switch when they are disconnected and you actuate them. The way you described it, you are supplying a ground via your test light. However, the grounds for each window is at a different point, so it doesn't make sense that they would all fail.
Confirm the switches are good and getting power and let me know if this all happened at one time.
Let me know.
Monday, October 5th, 2020 AT 8:11 PM