There is one thing that no one has mentioned. The colored plastic sleeves on crimp terminals indicates the size wire they are to be used with, and has nothing to do with polarity. Small red is 18 - 22 ga., blue is 14 - 16 ga., yellow is 12 - 10 ga., and large red is 8 ga. (may also be for 6 ga. - not sure on that). If you don't know this, the red ones can be very confusing,
Good job on troubleshooting and I'm glad you didn't let out the magic smoke.
Ken
Ken and Jeannette
2015 FunFinder 266KIRB - Traded in
2006 Ford F-250 "Super" Cab Long Bed - Traded in
2018 Winnebago Fuse 23A