If it has a manual tranny there's a safety switch on the clutch pedal that may have gone bad. Automatics have a neutral safety switch probably on the shifter on an '89. GM used purple 12 gauge wires for the starter circuit in '69. I don't know if that's changed for '89. As for the tumbler, it moves a rod back and forth that actuates the ignition switch mounted on the steering column under the dash. I'd make sure the switch is OK first. Hope this was helpful.
so I took down the panel under the dash, and there must be 500 wires under there, all in harnesses, so how do I know which one goes to the tumbler? and how do I test if that switch is bad?
Also, which 2 wires would I have to connect to "hotwire" it? I need this car on the road tommorow early, and wont have any time to dick around with it. So even a temp. fix will help a lot.