I am replacing the alternator in my 1996 gt and cannot figure out what the two cut wires go to. The diagrams I found only show one green/red wire going to the alternator, but I have another green/red coupled with a grey/red wire that have been cut by a previous owner and left unattended. Anyone with knowledge and/or a helpful wiring diagram, please help me figure out what these wires go to. Also, none of the gauges on my instrument cluster work and I’m wondering if this awful wiring could be the culprit?
‘96 mustang GT alternator wiring confusion?
- Thread starter _patgowen
- Start date
cobrajeff96
Well-Known Member
Ford is notorious for 'doubling up' wires in certain points in the harness. It's a way of attaining a thicker effective gauge wire without actually using thicker gauge wire. But just to be certain, buy a cheap digital multimeter and you can confirm this inside of a minute. Basically, the two GR/R wires are probably the same wire.
And it depends on what alternator is installed. It may not be the original, and so maybe the harness and connector had to be modified and someone did a barely enough good job of it.
The schematic attached is titled 4v but if you look closely at the diagram's branch circuits, it'll specify how the 2v wiring differs and it's only slightly. The other pdf might be helpful, it's helped me once or twice anyways.
For these SN95s, the alternator MUST have the instrument cluster in place and working properly. The alternator warning light is a part of the charging circuit. No cluster, then no working alternator.
A test you can try is to keep engine off, ignition on, battery fully charged:
The alternator warning light should glow. No glow means bulb has burned out or there is a break or bad connection in the wiring between the regulator plug and the instrument cluster. The warning light supplies an exciter voltage that tells the regulator to turn on. There is a 500-Ohm resistor in parallel with the warning light so that if the bulb burns out, the regulator still gets the exciter voltage.
Disconnect the D connector with the 3 wires (yellow/white, white/black and green/red) from the voltage regulator on the alternator. Measure the voltage on the Lt green/red wire. It should be 12 volts. No 12 volts and the wire is broken, or the 500 ohm resistor and dash indicator lamp are bad. If the 12 volts is missing, replace the warning lamp (it should just be a standard 194 or T10 lamp socket, probably not a good idea to use and LED instead of a standard bulb). If after replacing the warning lamp, the test fails again, the wiring between the warning lamp and the alternator is faulty. The warning lamp circuit is part of the instrument panel and contains some connectors that may cause problems.
And it depends on what alternator is installed. It may not be the original, and so maybe the harness and connector had to be modified and someone did a barely enough good job of it.
The schematic attached is titled 4v but if you look closely at the diagram's branch circuits, it'll specify how the 2v wiring differs and it's only slightly. The other pdf might be helpful, it's helped me once or twice anyways.
For these SN95s, the alternator MUST have the instrument cluster in place and working properly. The alternator warning light is a part of the charging circuit. No cluster, then no working alternator.
A test you can try is to keep engine off, ignition on, battery fully charged:
The alternator warning light should glow. No glow means bulb has burned out or there is a break or bad connection in the wiring between the regulator plug and the instrument cluster. The warning light supplies an exciter voltage that tells the regulator to turn on. There is a 500-Ohm resistor in parallel with the warning light so that if the bulb burns out, the regulator still gets the exciter voltage.
Disconnect the D connector with the 3 wires (yellow/white, white/black and green/red) from the voltage regulator on the alternator. Measure the voltage on the Lt green/red wire. It should be 12 volts. No 12 volts and the wire is broken, or the 500 ohm resistor and dash indicator lamp are bad. If the 12 volts is missing, replace the warning lamp (it should just be a standard 194 or T10 lamp socket, probably not a good idea to use and LED instead of a standard bulb). If after replacing the warning lamp, the test fails again, the wiring between the warning lamp and the alternator is faulty. The warning lamp circuit is part of the instrument panel and contains some connectors that may cause problems.
