Rain Sensor
 

I have an 83 yr old friend who drives a 2016 ES350 that has mostly been dealer serviced. He recently had a windshield replaced with an aftermarket glass because the original was cracked.
The intermittent wipers quit working coincidental with the windshield install. Professor Google says the rain sensor that sits next to the center rear view mirror is faulty so I disconnected it and the intermittent wipers work as they're supposed to.

I find it strange that the sensor quit working with the window install. I can easily buy another sensor and install it on the base that is already mounted on the windshield but I want to make sure that it will work before ordering parts.
Could the problem be anything that has to do with how the sensor is mounted to the glass? ie: could the glass installer have not cleaned the mounting base or done something else that messed up the install? Is there a way to test the sensor when it is removed and in my hand?

Thanks for the help.