Door micro switches - latch or handle?

[leftfield6]

My 99 Boxster has the issue where the window does not drop down/go back up as it should when the inside or outside handle is lifted. It seems like a common issue is failure of the microswitches inside the latch mechanism. So, I took a gamble and bought a "tested good" latch on fleabay for $40. Did NOT fix the problem.

Is there a definative way to test if it's the latch mechanism micro switch failing versus the handle microswitch?

I'm tempted to buy a new latch mechanism, AND a new handle microswitch just so I would feel reasonably confident of fixing this issue, but I hate throwing parts at an issue.