Hi Jeff, Had a quick look but not too certain what I am looking at. Was thinking about disconnecting it, but suddenly thought, what if that [an open circuit] is the signal to inflate ;-I Only got the old "eyeball Mk1" and no fluke handy, so cannot go much further. So have erred on the side of caution and left well alone. That said, may thinks for the response ;-) Cheese Grommet Max