Three words of advice from someone who does auto electric troubleshooting, firing the parts cannon should not become an option. Very expensive. When checking electrical connections, do not use only a meter. The high input impedence will show the worst connection as good. Use a test light, not LED, to verify that the connection or switch is indeed good. A high resistance connection will look fine with a meter, but unable to light even the smallest light bulb. And also, start your testing with clean and tight battery connections. Again a corroded battery terminal may look good from the outside, but underneath there may be high resistance that would steer you back toward that parts cannon.