What Mike said, or [neg] off the battery, key on, cable back on battery, and I mean just push it hard so you can start the bike = Not the switch.
Since the neg is off, scrape the lead post and cable side fresh with new metal, meaning, that contact each other. Do the same to the plus side since the neg is off on the switch test. Needle nose crimp, this side of crushing the soft lead if you prefer. That strong touch contact is good enough for the load to be normal and not heat up at that touch point. Then vaseline for the backyard mech, rather than run out to buy the right grease.