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Charging Issues

5tev30

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Dec 6, 2023
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Location
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i don’t get battery voltage at the alternator output post? what should i check next?

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I assume this was a running engine, and now it’s not. A little more info on your build would help with diagnosis.

With the key in the run position check the field wires to the alt for 12v. One of them , I forget which one, green I think, should have 12v. This excites/energizes the alternator. If you don’t have 12 volts going in, the alt will not work.

The 12v field wire is powered by the voltage regulator, so check to see you got power going in & out of the VR with the key in the run position. This is likely your problem… could just be a bad ground, so try it with a separate ground, jumper wire.

If you do have 12v going into the alt and still no output when running check both ends of the output cable for continuity and good clean connections. Do you have 12v at the starter relay, or did you do an ammeter bypass and run the output wire directly to the battery? If all the connections are in order, and it cranks over, you prob have a bad alternator.
 
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yes zero voltage at alternator output. i traced wire to firewall and found this. is this my fusible link? some context: the car died died at a traffic light. i jumped her and she ran off battery to a parking lot. i replaced the alternator and voltage regulator still no charge at battery.
 
The fusible link is on the battery side . come of the relay. the red and green wire that bolt on the relay. green is the link it unplugs from the red by the master cylinder.
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Follow the dots. understand how it's wired first. Blue charge circuit, yellow battery supply, red ACC circuit.
1:RED wire 16 Battery power yellow dot to splice one feeds fuse block, 2:charge wire 18 black wire blue dots to splice one through amp meter to red wire blue dot 16 to battery, 3:ACC feed from splice 1 Red wire Q3_12R yellow dot to steering column. Black wire 12BK red dot to ACC side of fuse box.ch load.

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thanks guys i’ll read up and looks things over in the morning drive safe
 
Follow the dots. understand how it's wired first. Blue charge circuit, yellow battery supply, red ACC circuit.
1:RED wire 16 Battery power yellow dot to splice one feeds fuse block, 2:charge wire 18 black wire blue dots to splice one through amp meter to red wire blue dot 16 to battery, 3:ACC feed from splice 1 Red wire Q3_12R yellow dot to steering column. Black wire 12BK red dot to ACC side of fuse box.ch load.

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I don't ave a rally dash however could you please share a wiring diagram from the alternator output to the firewall or battery
 
In general the charging and other circuits are the same.
look at the amp gauge. The red wire comes through the bulkhead connector. The black wire goes to splice 1 feeds all loads from the alternator, acc through the ignition switch and acc side of fuse block. Check to see if you have power at the fuse box on the battery terminal .If not check bulkhead connectors. acc terminal will be hot when ignition switch is on. If not check the under column plugs.
Keep in mind when battery is connected that circuit is always hot.
 
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