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Discussion Starter · #1 ·
Changed out the alternator(internal voltage regulator) on our 76 El Camino, 350, yesterday. Started right up, volts reading 14. Parked it last night. 24 hours later, dead. No lights, no start, nothing. I pulled the battery cables and cleaned them up,the battery is less than 60 days old. The alternator is new, not rebuilt. Any suggestions?
 

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If you jump the car, does it start? If it starts, what is the voltage, on the battery, with the car running at idle? Around 14 volts should be OK.
Was the battery low in the first place? Alternators are not true battery chargers and won't recharge a very weak battery.
If you have gotten this far, the problem may be a drain on the battery. It's also possible that your new alternator is the problem. It can put out but contain a partial short that drains the battery. Check the battery for a drain using a test light on the negative cable.
 

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OK now I see what you mean.
Did you try jumping it with the ground (negative)jumper cable to the block on your car? I'm assuming that the ground connection to the block isn't any good and changing out the alternator disturbed it.
If that's not it:
Other possibility is the main fusible link may have popped. I can't tell you where to look or measure until later. I won't have access to any books until some time this evening.
 

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If that didn't help, measure the large red wire, on the back of the alternator, to ground. See if it measures 12 volts. If it doesn't sounds like the problem is the main fusible link down by the starter.
 

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Discussion Starter · #6 ·
An update. Pulled and charged battery. Replaced Negative cable, re-cleaned block and body grounds. Still nothing, no lights, no horn, dead.
 

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Discussion Starter · #8 ·
Large Red Wire at back of Alternator: don't have one. I have a connector with brown and blue wires, and a black wire to the stud.
 

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Measure the alternator stud wire to ground. You should see 12 volts to ground with the key off.
 

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Larry
The Haynes manual I have shows that the black wire you have on back of the alternator should be a red 10 gauge wire. Someone has changed it out for some reason. I'd try to follow it back to the starter solenoid and see if there are any poor connections/splices or bare spots touching ground.

According to the diagram the wire goes from the starter to a junction point ( non specific as to where? it is) From the junction point it splits off in 4 directions. 2 of those wires go to the back of the alternator, 1 to an underhood lite and the last goes to the firewall connector and into the interior. The 2 that go to the alternator are to the Stud and to the "V" connection on the plug in connector. Make sure that it is connected to the "V".

On my 72 the junction point is a relay behind the master cylinder. I'd bet that the 76 is similar. If you disconnect a battery cable you can use the ohms function of your meter to check if the wires are connected.

I may be missing something but do you think that the alternator/battery is not charging? OR do you think that after running it is fully charged and then slowly draining off? Sounds to me like a slow discharge. Possibly due to an interior/underhood lite that doesn't turn off or a short somewhere.
 

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Discussion Starter · #11 ·
Rick & John: I got it fixed. The long explanation is in the Toubleshooting section. I replaced the Alt. because the voltage output was so low when the elect. systems were turned on. I probably did something wrong when installing the alt. I ended up replaceing the positive battery cable, solenoid and starter. It started yesterday, hopefully it will start tonight. If not, I may just replace all of the wiring. The people that had the car previously have made a rat's nest of the wiring and a couple of other systems. One at a time.
 
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