It sure is a pain in the ass to get to the upper clutch pedal sensor without taking the pedal assembly out of the car. I had a clutch replacement done about a year ago (including all hydraulics) and my shop didn't attach the upper sensor to the pedal (although it is still connected and no defective). As a result I now have to press both clutch and brake pedals to start the car and also now have to hold the start button until the engine fires. Cruise control still works normally though thankfully, because I simply can't reach the upper sensor.I have the same exact issue, I changed the CPP sensors but there are 2 and one other member had the same issue and ended up changing it for the third time to get a good working sensor.
I haven't changed the the upper side sensor yet, its pain in the ass but I did change the master cylinder pedal assembly when I put in a new clutch.
You can test it by reading the CPP switch readings should should 50-100 and 0-50 something like that mine is either 66.7 or 100%.
I am guessing your cruise control wont turn on too as safety measure?