Yes, but looking at contacts open and close is different than using a multi-meter and looking for change of state.
Powered contacts will have voltage across them when open, and go to low voltage when closed.
Check grounds with meter, by measuring back to battery (-). Voltage should be near zero.
Rivets are sometimes used to attach contacts to wiring or terminals, they can oxidize and make open connections too.
Good sharp probes really help, most cheap meters have cheep iffy probes. Learning to probe around with meter, helps with fixing success. Use meter to investigate all points and connections.
A thin strip of new printer paper carefully pulled through contacts can clean them. Be careful not to bend them.
Small clean stainless steel brushes help clean male Fast-on terminals. Female Fast-on terminals get brittle, and loose grip. Fast-on terminals are only rated for a few plug cycles (3-5). Bulkhead terminals troublesome in our old cars.