Check engine light
Got the check engine light, went to AZ, they scanned it and the print out said P0671 Cylinder 1 glow plug circuit.
I checked the connections, removed and reconnected, and they seem good, no corrosion. Have not yet checked glow plug resistance.
Is this likely to be a deteriorating glow plug, or wiring, or controller? Looks like a separate wire for each plug, which is not what I'm used to on other (marine) diesel engines. The black harness around the glow plug wires is cracking, but that just looks like a chafe guard, not really part of the system electrically.
Tips on clearing the light to see if I've fixed it?
Also, what is the diaphragm like device with lever, passenger side back of engine, looks like it's part of turbo control? It has a small telltale hole that I'm getting a little bit of black oily liquid out of, not much.