It was something simple, lol I panicked & did not think, got to look at it some more after work today!.. I have the temporary battery terminals on my Dart & the 2 top bolts worked loose on the ground!
glad it was something simple, and you found it.
however, that type of cable end is one of my most hated electrical items ! whenever i see those on an otherwise nicely detailed engine bay, i cringe !
you have correctly identified that as a TEMPORARY terminal end. please install a new, permanent end if the cable is long enough to do so, or replace the cable[s].
it will be better for you in the long run, and i won't get the jitters just thinking about those ends.