Found the fault. Turns out that when I put the last remaining engine mounts on I crushed the wire just above the rear brake light switch
I'm curious how you found the problem - was it visually by following the loom covered cables or by following Larry's instructions? If the latter how did that narrow it down?
I went back to your first post and reread this thread. I was curious about the path to the solution.
@ST_SVK was the first to suggest a pinched wire, I reiterated his idea and pointed out that when something stops working after a project, it was usually that work that caused the failure (which you denied ("I only changed the engine")).
@Andrew Shadow also supported the pinched wire idea.
I'm not trying to assign any blame here, I'm trying to figure out how best to troubleshoot electrical faults. As an electrician, I found the problem was most often visually identifiable and obvious once I looked in the right place.* Tracing a circuit was usually slow and laborious, and did not bear fruit unless I was dealing with multiple splice boxes with many wires. We learned an important troubleshooting technique from
@Larry Fine here, and it will help many of us.
*Residential electric codes do not tell the electrician where to run his wires and blue prints are rarely available. Even if they are, outlets, switches and lights are simply shown as symbols and the circuitry is up to the installer. An electrician may make a splice in the conductors for a circuit in any convenient box, even if it is not part of that circuit. Finding that elusive loose wirenut then becomes more an exercise in logic than electrical theory. Often 'local knowledge' - how the old guys wired things is more useful than your tester.
I'm very electrically handicapped.