At this thread it was said that it cannot be jumped:

http://www.peachparts.com/shopforum/showthread.php?t=59565&highlight=w140+compressor

How would I dry charge, after removing my vacuum pump, I attached a can of Freon through low-side and the pressure in my guages indicated 80psi, but the compressor didn't kick on. Everything worked fine before changing a cracked A/C line and dryer.