Have a 1971dodge dart swinger with voltage drop issue. While looking at the under dash harness plug that goes to the ignition switch harness plug, notice that red wire and black wire were always 12 volts. The ignition switch plug black wire(accessory) was 12 volts in run and accessory position. So in run position i would have under dash and ignition switch black wire both at 12 volts. I thought the under dash harness provided battery voltage to ignition harness through the red wire then the switch would provide voltage as needed if in accessory, run, or start positions. New at this. So question is should under dash harness black wire always be at battery voltage. It will receive voltage through the ignition switch when the switch is in the run position, then its 12 volts on 12 volts. Thanks for any info on this.

 

Under dash for the most part is 12 Volts...... Dash cluster has a resistor to drop voltage.... Only other resistor that i can think of under the dash would also be for the Heater and A/C, if so equipped.

 

Thanks Bob. The voltage limiter will do that drop for the gauges. I get a 2.4 volt drop from battery positive to voltage regulator. Just have to hunt for a bad wire or more which brought me to the under dash harness. Just can not understand why the ignition switch black wire would provide 12 volts to a wire which already is wired for 12 volts. If that should not be than i will have to tear apart under dash harness to see why. Or buy a new harness at $700. If that is correct the way it is i would have wasted 700. Again thanks!

 

You should have 12 Volts on the Dark Blue w/tracer wire.... From the ignition switch out to the voltage regulator....
Check the connection at the bulk head connector...

Also, try jumping the AMP gauge and see if that helps with the numbers...

 

Will do. Thanks