Air Conditioning A/C Pressure Switch

[Bigmacneb1]

This is in addition to my previous thread. Attempted searching, but searching A/C is not possible.
Anyway. My compressor keeps cycling on and off every ten seconds even though I had it recharged with what the shop said was a pound of refrigerant. This recharge did not change the cycling compressor problem.
My Aux fan stays on , so I believe it is not that.
The other two things I can think of are the Pressure Switch or maybe a relay? or maybe the actual A/C button??
If I replace the switch, has anyone done this? Does the system need to be drained first?
Thanks guys.

[dhirsch]

I'm pretty sure if you change the pressure switch you'll have to evacuate the system first.

[kenika65]

Did you ever figure this out? I am having the same exact problem, my compressor wont come on but every thing else is working correctly except when the compressor turns off the blue a/c switch flickers? I am confused because everything checks out good?

Hope you figured out your problem.