Could be electrical ... i.e., loose battery cables ... maybe activating the trim kept the e-circuit intact.
I'd bet $$ you run wing nuts, they could be loose. But IMHO lock washers still should be used on battery posts (above AND below the battery cables) for secure and TIGHT connections, see picture attached below.
THROW AWAY any wing-nuts and use only Nylok nuts on ALL battery/cable connections!
POS Post: 3/8"-16tpi, std coarse thread (9/16" box wrench or socket)
NEG Post: 5/16"-16tpi, std coarse thread (1/2" box wrench or socket)
FYI - Have you noticed that newer batteries are coming out with the same size post (5/16") connections? Mandated by law, it appears "loose connections using wing-nuts only" makes such a poor and high resistance connection that can produce quite a bit of heat under load, so much so that studs have melted right off the battery. Plus, with such heat, all sorts of bad things can then happen, e.g., such as fire or explosion :shock: .