How do I get my ac compressor to run to recharge? 95 Mercury Tracer?

I have a 1995 Mercury Tracer 1.9 and I had to replace an ac line because the high pressure port was leaking and the Schrader valve could not be replaced. I am now attempting to recharge the ac but the compressor isn't turning to suck the freon in. When I jump across the low pressure switch all it does is activate the relay not the pump.