97 deville a/c

I have a 97 deville that needs a/c freon, but the compressor is not working because of low freon, it went off. How can i get the comp, on so the freon will go in, last year a friend placed a jumper so were under the hood and the comp. Went on .but he moved....thank you...

Turn the system switch on and set to max cooling. The compressor may kick in as you add the freon and the system pressure rises. Or you can jump out the low pressure switch across its terminals.

I know this is an older thread, but here's my 2 cents anyway - Jump out low pressure switch by acculator with a bent paper clip. Do this with ignition off, before starting to charge system!