1973 Duster Electrical Issue
Let's begin with the power supply.
There are two power supplies for the car.
Power flows from whichever one can supply at the higher voltage.
The output wires from the battery and alternator are joined at a welded splice under the dash.
That welded splice is also a junction to feed the main circuits:
Dome light, parking and marker lights, brake lights, horn, all get power directly through the fuse box's hot buss.
Windshield wiper switch gets power only when the key is in accessory or run position.
Heater fan, Radio, Reverse lights, and Turn signals only when the key is in accessory or run position.
On 1973 models, the heater switch, reverse lights, and radio share a fuse and wire circuit to the turn signal flasher.
Hazzard flasher is seperate. Power is available to it even with the key off.
Let's begin with the power supply.
There are two power supplies for the car.
Power flows from whichever one can supply at the higher voltage.
- Battery can supply power at approximately 12.5 Volts.
- Alternator will supply power at approximately 14 Volts.
The output wires from the battery and alternator are joined at a welded splice under the dash.
That welded splice is also a junction to feed the main circuits:
- Key switch (wire J1)
- Fuse box (fuses that are always hot) (wire Q3)
- Headlight switch power for headlights (wire L1)
Dome light, parking and marker lights, brake lights, horn, all get power directly through the fuse box's hot buss.
Windshield wiper switch gets power only when the key is in accessory or run position.
Heater fan, Radio, Reverse lights, and Turn signals only when the key is in accessory or run position.
On 1973 models, the heater switch, reverse lights, and radio share a fuse and wire circuit to the turn signal flasher.
Hazzard flasher is seperate. Power is available to it even with the key off.