What Sensors Are These Etc

[Kezzer30 40 1 Cars]

I'm wanting to learn as much as I can about my 1.9 and there's a few things I'm not sure what there are etc

what are both of these located through the gap of the alternator and inlet manifold .

 

this sits on top of gearbox and this has not being connected on mine for I assume all the time I drove it lol

 

these two are located round the back of the thermostat cheers

[j_turnell 137 3 Cars]

Oil pressure switch and sender top pic, second pic is the reverse light, and bottom is water temp gauge and warning light.

[Kezzer30 40 1 Cars]

Thank you buddy , the blue plug on side of thermostat is the water temp sensor and the plug sat on bottom of sump is the oil temp sensor is this correct ?

[Anthony 1,003]

Yep - coolant temp sensor for the ECU and the oil temp sender for the dashboard guage