[390fastback]

Don't quite understand, you said when you have it on the dash lights and tail lights are on, but the light switch is off. Do you mean the ignition switch is on, clarify please. Maybe I missed something, this late that happens.

Someone please buy my Ski Doo!
68 fastback
80 5.0 hatch
91 5.0 coupe

 

[Guest]

I suppose there's enough current draw INITALLY to not let the starter do its thing, but the starter is hardwired to the starter solenoid (and battery), while the headlights go through a switch. However, incandescent bulbs draw 10x their steady state current for a few milliseconds, while the filament is heating up; batteries are designed for inrush currents.

I'd check your starter circuit first, including the ground wire from underneath #1 cylinder (near oil pan) to battery "-" terminal. A loose connection could cause your starter to not engage the flywheel teeth, not to mention sparks and other ugly electrical dangers.

BTW, when you check anything having to do with the battery, remove the positive batery terminal first, as a safety precaution.

Perhaps the battery is undersized??

Thanks,

Mike
'66 Springtrime Yellow Coupe
289, slightly warmed over
driven daily