I had to go to a parts diagram to find where to replace a low oil pressure switch on a M5030. Once found could use wrench to take off. Wife had to start new switch. Hands and arms too big without major disassembly.
I'm gonna take a stab and this and say it might be located near or on the intake manifold. That's where it is on my BX and on every car I've worked on had it there too.
The sensor is usually located (my experience) where the water will be hottest. This is near the thermostat on the way back to the radiator. Look near the top of your engine near the front - frequently (but not always) on the right (starboard?) side.