Did some (amateur) electrical diagnostics today.
The connector to the pump has 2 wires, a grey and a black. I believe the black is ground, and I think I managed to locate the other end of the grey wire going into a connector block on the CEM (
B2 #14).
I tested for continuity in both wires but didn't get it in either. (For the black wire I tested it from the pump connector to the black wire on the indicator connector as it was handy.)
So it seems both wires have failed somewhere?
As it doesn't look like I can dismantle/replace the connector easily, I'm thinking the next step is to splice new wires in just before the connector using Scotch Lock clips, then test to make sure the connector isn't the problem, and if it's fine, route the new wire appropriately and spice onto the wire just before it goes to the CEM (and splice the ground into a nearby ground).
Does that sound sensible?