If it has a low pressure cutoff switch it must be bypassed to allow the new freon to get pumped in. when you bypass the cutoff switch you will hear the compressor clutch go "click" only then add the freon you will feel the can or line get cold- hold it up and turn it over for a few seconds at a time and check for cooling in the car. you really need to know how much to put in and use gauges too. If you don't get the click from the compressor clutch you can't proceed until that is fixed. the low pressure switch is usually somewhere on the large line or the accumulator and needs to pulled off and a wire put in the socket to make the connection. Do NOT leave it like that if you get it charged up it must be put back on.

If you charged it and the compressor clutch was engaging and then quit engaging, you have a huge freon leak that will have to be repaired before you charge it again. Did it have any pressure in it when you first charged it? If not, were you able to pull a good vacuum on it before you charged it?

Check wires or could need a new 1

check the relays

So I have 1995 Mercedes Benz c220 2.2 liter 4 cylinder and it does have some electrical problems regarding electric starter and such. So I didn't have any freon and decided to have it filled up put all new freon and tried it but compressor would not kick on it was turning but would not come on resulting in no cold air. Checked the fuse box no blown fuses I know you can jump it but I'm not sure what wire and Mercedes are weird and don't want to mess something else up especially since it has problems please any help or advice thank you so much