Measuring IR sensors??

My IR sensor on the driver's side does not do anymore (passenger side goes), because this particle is unfortunately not quite cheap (EUR 100) I would like to measure it before, in order to exclude a cable break -> is that possible?

In the worst case, I have to open the B-pillar on the side of the vehicle and exchange the sensors, then at least I know what I am... But maybe someone has already gained experience and can spare me that.

THANK YOU!