In the picture above, it's the part between the pulley and the compressor (with the 2 wires coming out of it). I got that compressor from rockauto for ~$150, but my compressor was froze-up (I needed it). If your system is charged and working (other than the short issue) and you're sure it's only a stater, then I wouldn't replace the entire compressor. Makes much more sense to replace just the stater. Replacing the compressor will require the system to be evacuated, the receiver/dryer replaced, and they system recharged (expensive). If it's just a bad stater, you can just unbolt from the front of the compressor and replace (no need to drain/process Freon). Everybody has their opinions, but seems that the professional mechanics always lean towards the most expensive ones
. Tim