That's the same sensor I bought for my 560sel (by appearance). You cannot change it without evacuating the freon first. From very helpful people on this forum - I have learned that the sensor causes the aux fan to come on low speed when freon pressure from the air conditioning running switches it on. I was all set to condemn my sensor (even bought a new one) when a couple of people on this forum advised me that if your freon is a little low - the switch will not work. When I get my car out of storage in a week or so (we just got 4" of snow!)- I will try to top it up and see if they are right. If not - I will convert to something (R134 - freeze12- whatever - haven't decided yet)and replace the sensor at that time. If you are really low on freon the compressor will not run to prevent it from getting damaged. Check the freon in your sight glass - if you cannot see any - that's it. If it is foamy - you need a top up.
Just my experience to date
Maurice