I'd hate to see what the internals of the motor look like.
Unless you have expertise in this issue (electrolysis/leakage current/grounding issues you should get a qualified professional to fix this ASAP. If using a multimeter, it must be capable of reading small fractions of ohms/current/voltage. As gungadin has mentioned, something recently came loose/failed/corroded. For all connections you need lot's of CLEAN contact area.
All ground NEED to connect at a single connection point; check the the neg battery terminal isn't "overloaded" with connections; according to ABYC 3 lugs max per per stud/bolt.
Doubt a cheap meter will suffice for this.
Unless you have expertise in this issue (electrolysis/leakage current/grounding issues you should get a qualified professional to fix this ASAP. If using a multimeter, it must be capable of reading small fractions of ohms/current/voltage. As gungadin has mentioned, something recently came loose/failed/corroded. For all connections you need lot's of CLEAN contact area.
All ground NEED to connect at a single connection point; check the the neg battery terminal isn't "overloaded" with connections; according to ABYC 3 lugs max per per stud/bolt.
Doubt a cheap meter will suffice for this.