1979 Chevrolet Truck Chevy Scottsdale battery keeps dying

GGALLIMORE1979

MEMBER
1979 CHEVROLET TRUCK
V8
2WD
AUTOMATIC
200,000 MILES

I have a1979 Chevy Scottsdale. Have had some issues with engine power and acceleration, but biggest problem is that the battery keeps dying. Last week, while driving after getting it jumped off yet again, it sounded like my starter tried to re-engage and got stuck. Shut it off, noise didn't stop, had to pull battery cable to get it to stop. Mechanic said bendix in starter/solenoid was bad and that that would cause my battery to die, if the bendix was going bad it would drain the battery and that it finally went completely out that day. Replaced starter, jumped it off, ran fine except lost headlights and turn signals. Got it home and shut it off and wouldn't start back up again. Tested alternator, bad alternator, replaced that, still will not start unless it is jumped off each time and I still have no headlights, but replaced a fuse and got turn signals back. I am at a loss as to what to check next.

5 Replies

JDL

MECHANIC
16,098 POSTS

Are you sure the battery is good? You can use a digital multimeter across battery posts, the generic spec for a full charge is around 12.6 volts. If the battery is down, take it off and get it charged. You shouldn't let the alternator charge a down battery.

With a full charge, start the vehicle, take second reading across across battery posts, the second reading should be higher than the first, if charging system is ok.

As far as battery drain, with key off, the old way to test, was take battery cable loose, use a testlite between cable and battery post, if lite came on bright, you have a drain. Make sure no lites on anywhere, under the hood, interior, anywhere. As far as lites, the best time to check is in the dark.

If no lites on anywhere, then you pull/replace fuses one at a time, when you pull the fuse on a problem circuit, the lite goes out, then you check everything on that fuse circuit.

Sometimes a faulty alternator can drain battery, but the alternator is new, correct?

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Monday, January 20th, 2014 AT 2:54 PM

GGALLIMORE1979

MEMBER
2 POSTS

Yes, new alternator, have had the battery to autozone for a charge, they said it was good and we had 100% charge, drove it from home to there, to ask about headlights, 5 blocks, then home again, and battery dead again. And still no headlights either. :/ Frustrated!

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Monday, January 20th, 2014 AT 3:01 PM

JDL

MECHANIC
16,098 POSTS

What model of chevy truck do you have? I'll try to look up headlamp wiring? I already told you how to check for battery drain. The alternator bat terminal, with the key off, any voltage? Unless you can do a little testing, I'm not sure how to help?

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Monday, January 20th, 2014 AT 3:58 PM

JDL

MECHANIC
16,098 POSTS

Mt bad it's a scottsdale.

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Monday, January 20th, 2014 AT 3:59 PM

JDL

MECHANIC
16,098 POSTS

As far the headlamps, I'd have to check voltage to and from the headlamp switch. Then through the dimmer switch.

Did you check for voltage and ground at the headlamp connector? The tan wire and lt green are voltage for high beam and low beam. Black wire is ground.

Headlamp switch gets voltage through red wire, hot all the time from fusible link. From the headlamp switch lt blue wire carries voltage to dimmer switch. From dimmer switch to head lamp, lite green wire is voltage for bright. Tan wire is voltage for low beam. Use a test lite to check for voltage.