The internet vs mechanical repairs

So the Sprinter is the first new(ish) enough vehicle I've owned to actually have brake pad wear sensors. They're common on virtually all vehicles nowadays, despite being more of a novelty than anything else.

But discovering how these ridiculously simple parts work is extremely difficult in an internet world. Correct mechanical *advice* for virtually every topic, part, real or imagined is incredibly difficult to find. These brake sensors are quite magical if you start trawling forums, youtube, and general car help forums.

Possibilities include:
• It's an open circuit that shorts against the rotor and signals the pad is worn.
• It is a magnetic sensor.
• It's a resistive sensor that changes impedance as the pad gets low and should be XYZ ohms when new.
• The metal clip is a sensor and very delicate.
• The sensor incorporates "electronics".

However none of these are true in any make or model, year or timeline, this universe or the multiverse, yet most of them are the PREVALENT explanation.

How it really works:
• It's a closed circuit. Impedance if any is irrelevant and not measured.
• The metal clip is just a springy metal clip to assit in keeping the plastic sensor secure in the brake pad cavity.
• When the brake gets low, the little plastic nubbin on the ROTOR SIDE of the clip wears down and breaks the circuit where the wires previously traversed.
• Dash light goes on.
• Part is consumable and cannot be re-used. It is literally worn down like the brake pad.
• ...the end...

So thanks to the internet, I once again had to spend excessive time trying to diagnose multiple options that may or may not be true, until I finally conclude which combination is the only and obvious choice. If the sensor is a closed circuit and is unplugged/absent/damaged/used, this will trigger a brake warning as an open circuit is detected. Otherwise everyone would leave the sensor unplugged and not replace them. This is the only combination of events that makes sense, keeps costs low, and is reliable.

Thank you internet. You cost me many brain cells for something very simple yet again.

ps: Don't arbitrarily replace pairs. Just replace the one that tripped the fault. Go ahead and replace pad sets left/right if you want for convenience...but re-use undamaged sensors.