If its has pressed in diodes (round back), letting them fix it is best.
Your's looks clean in the photo. If you care about originality, tell them not to sandblast the housing. It obliterates the stampings and casting numbers.
Charging issue 68 barracuda
- Thread starter mikewadkins
- Start date
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Your's looks clean in the photo. If you care about originality, tell them not to sandblast the housing. It obliterates the stampings and casting numbers.
67Dart273
Well-Known Member
Don't make this so complicated. I tend to divide these problems into sections
1...The alternator output circuit, that is the path from the alternator stud, through the firewall, the ammeter, the welded splice, back out the firewall, and to the battery. If when running, the alternator stud is "off the map" and the battery voltage is low, then you have a poor connection in that circuit
2...The Field circuit. You must have "same as battery" at the blue field wire with key on/ engine stopped, and same thing at VR "ignition" terminal.
3....Ground. If it's charging at all.......and it ain't......the VR mounting flange must be at same voltage as battery NEG
4....Easy to jump around the VR and see if the alternator can charge. On 69/ earlier you have a field that is GROUNDED on one end and just one field wire. So jumper battery power into the alternator ffield terminal and see if it charges "full tilt." This tells you whether or not the alternator is good. Double check the output at the alternator stud see "1" above
On 70/ later you have two field terminals. One gets (blue) battery voltage from the key, the other (green) controls "the ground" through the VR. Ground one, feed 12V into the other and see if it charges
5....If Jumpering the field in 4 above causes the thing to charge, double check that you have battery voltage getting to the IGN terminal of the VR, double check that THE VR MUST BE GROUNDED, and check that the continuity of the field wire to the alternator is good. If all this is OK, replace the VR
1...The alternator output circuit, that is the path from the alternator stud, through the firewall, the ammeter, the welded splice, back out the firewall, and to the battery. If when running, the alternator stud is "off the map" and the battery voltage is low, then you have a poor connection in that circuit
2...The Field circuit. You must have "same as battery" at the blue field wire with key on/ engine stopped, and same thing at VR "ignition" terminal.
3....Ground. If it's charging at all.......and it ain't......the VR mounting flange must be at same voltage as battery NEG
4....Easy to jump around the VR and see if the alternator can charge. On 69/ earlier you have a field that is GROUNDED on one end and just one field wire. So jumper battery power into the alternator ffield terminal and see if it charges "full tilt." This tells you whether or not the alternator is good. Double check the output at the alternator stud see "1" above
On 70/ later you have two field terminals. One gets (blue) battery voltage from the key, the other (green) controls "the ground" through the VR. Ground one, feed 12V into the other and see if it charges
5....If Jumpering the field in 4 above causes the thing to charge, double check that you have battery voltage getting to the IGN terminal of the VR, double check that THE VR MUST BE GROUNDED, and check that the continuity of the field wire to the alternator is good. If all this is OK, replace the VR
mikewadkins
Well-Known Member
i just got the new alt and sent the new style square back. My old system had the 2 wires. I dont really care what alt is on as long as it works and not rigged. The square back has 3 wire hook up. If i read other replys correctly i would need to ground one of connections to make work?
67Dart273
Well-Known Member
Yes, ground one field. It does not matter which one. BE DARN SURE you check that one is not ALREADY grounded, this is way too common. Take your multimeter and check the field connections to the alternator case. Before you apply any jumper, it should be "open" (infinity)
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