Hey folks, I'm working on the '70 again, my dashboard lights aren't coming on with the headlights, I've successfully removed the dashpad and gauge cluster, and bought a new switch... and cleaned more connections than I thought I ever would. Any troubleshooting tips? I've got time to kill.
Not sure how close the 1970 switch is to a 1966 switch...but:
you will use some variation of this...the "I" terminal is power for the instrument cluster...do a continuity test between that terminal at the harness connector on the switch side and corresponding wire at the connector on the cluster side. This will tell you if there is a break anywhere in the wiring. If there is continuity, then the problem must lie somewhere in the cluster itself.