A lot of VM1000 issues get fixed by resetting the ribbon cable.  That's the first thing I'd try.  Just pull it off the main display and any other indicators and reattach it.

Another weak point is the junction of the sender wires into the main computer.  There are a couple different types of wire attachment.  The screw-type connectors aren't as reliable as the D-sub type.  They're usually a real pain to access and retighten, but many times that helps too.