AC don't work
 

When i bought my 98 Z-28 last July i noticed the fenderwell sticker saying that tracer dye has been added to the AC system because of leaks.It seems to be coming from the back side of the compressor but over the winter months enough has leaked out that compressor won't cycle on .My question is how do you get system to run to add some 134a.The low pressure switch plug has 3 wires instead of 2 so how do you make a jumper wire to make compressor work.I am sure 1 of those wires go to the PCM.I gotta get it fixed sometime but will try this for now. thanks