Turn signal quandary

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New to me 1978 C10

I had various lights out on all corners, so I went through and replaced all the blinkers, running, brake and backup lights. I also went though all the grounds, cleaned and dielectric greased them all. I also yanked the blinker relay and cleaned the blades and dielectric greased it.

So at this point everything works as it should, except the blinkers.


They work fine when the headlights are not on.

When I turn the headlights on, the blinks are sporadic (side markers blink opposite of the front running lights and are dim).

Now here is where I'm at a loss....

If I start the car and rev it up everything works as it should (blinkers work as normal).

At idle the alternator is putting out 13.4 to 13.3. When rev'd up, it's puts out 14.5 (this does not change when the headlights are on or off).

Now I had the battery down to 80% (according to my "smart" battery charger) as I had the lights on and off most of the evening while trouble shooting grounds and such.

SO....

Will a battery at 80% make the turn signals act like this?

Is the blinker relay temperamental to a low voltage situation?

I appreciate the help, as this is an oddity to me.

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