Dear nedc,

May this find you well. I've never swapped engines: that's way above my pay grade. I salute you for undertaking this.

While 2 AMMs could be bad, it seems more likely that there's a faulty ground. I don't have any 960 wiring diagrams, so can't point you in a specific direction, in terms of where to find the ground(s). Some of the on-board experts should be able to do so.

At the risk of driving your blood pressure up into four digits, check all grounds - clean and treat them with aerosol de-oxidizer. You seem to have done everything else, that's reasonable to do.

Wishing you every success, I remain,

Yours faithfully,

spook