1989 Chevy Silverado voltage regulation

1989 CHEVROLET SILVERADO
240,000 MILES • 6 CYL • 4WD • AUTOMATIC
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CCOBURN
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The voltage flickers on the volt gage while the headlights and heater fan go up and down at the same time.

It happened last winter, not while warm, and does this again now.

Seems like a regulator, but it is integrated into the alternator. I changed that last year.

I have no idea what would make the alternator go from zero to full field if the regulator is new - and supposedly good. There is a single wire in a plug going in the back of the alternator. I'm not sure what it does.

Everything is clean and tight.

The temperature correlation has me stumped.
Dec 8, 2009 at 10:24 PM
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JDL
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Welcome to the forum. I'd double check the charging system. Alternator output can go up and down with rpms. You may have to check for voltage drop on the wiring circuits?

It is possible to wire relay into headlamp circuit, that way main voltage for headlamps comes from relay, not headlamp switch.You could place relay close to battery. You would need to use fusible link or fuse on circuit from battery to relay. I'm just thinking out loud, doing that might not even help?
Dec 9, 2009 at 12:12 PM