I just pull them straight up out of the box - I'm pulling the 6.2 which I believe is engine/fuel management. That's the one that's heating up with the key out. The IAV stays hot as well for as long as the battery stays connected - hence the discharge of the battery during the 5 days it was running after engine replacement. Last night I replaced crank position sensor and cam position sensor - no change. The ecu's are from a Volvo only salvage place that I trust implicitly. And I've tried three more beyond original so I think the odds are against all being bad. But then, the odds are against what's happening now! I have a good used harness to try so maybe that's the next step?