Dead battery

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1970PAValiant

1970PAValiant

master of the break down
Joined
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Well tonight I was going out for a cruise around town and my car wouldn't start, Earlier today the dashlights would dim and the turn signals wouldn't work unless I reved the engine up. Got her jumped and the Voltage meter in the car was showing -20 until I reved up the engine to higher rpms just to get it to 0. A few days ago it was fine but now it's acting up. Gonna go down to the local parts store and see if they can test her. Any Ideas?
 
Sounds like the alternator may be on the way out.
Check the belt tension first to be sure its not slipping.
Test the alternator. With engine running, put a wrench or ? to the back of
the alternator dead center. If its charging, there will be a magnetic pull.
 
I actually checked the belt tension 2 days ago since the belts are 2 weeks old and adjusted them. my friend said it might also be a dead battery cell? I'll go test the alt tommorow too
 
There are many posts on this. Search.

One way to check the alternator is disconnect the "FLD" wire at the voltage regulator and apply 12 V to it. The alternator should then put out full current. If not, assure you measure 12 V across the field terminals at the alternator. Often the problem is you don't get a good ground connection from the low terminal which connects to the case in the early alternators (1 field wire). If so, run a ground wire to it or remove the alternator and sand the corrode aluminum body where it contacts the brackets.

Notes:
If old-style mechanical reg, you can actually leave FLD connected when you externally power it, but that might damage an electronic type.

If you don't have a multimeter, they are often $2.50 at Harbor Freight Tools. I have one in every car.

If the alternator puts out full, the problem is your regulator.
 
You could also have a corroded/broken post on your ammeter gauge in the dash. if you run a 14 ga wire from the fld terminal on the alternator to the positive battery post and see if the battery starts charging, then it's not the alternator. Check Bulkhead wiring connectors and also search for any broken/worn wires in the harness which may have grounded.
 
ok well got the alt. tested and it was only doing a 1/2 charge. New one for me in stock. Also got some new terminals since I saw 2 were frayed
 
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