In the top -front middle of my SD 709 compressor, there is a wire attached to the body by a screw. Mine is not connected to anything, and I see no other free wire ends in the engine compartment. I see on pictures of new compressors on vendors sites that they come with these wires. I thought it strange that the compressor would require an additional ground (which is what I first took it for), so I checked the Bentley and the only reference I could locate as to what it might be had to do with a compressor overheating fuse (I haven't had a chance to open the side pillar and look for it, yet).
Is this what this wire is for, or is it for something else? Where do I connect it? What issues does/will it cause by being disconnected?

Thanks,
Robert

'87 Vanagon GL