ballast resistor

vscummins · Jul 27, 2015

i have a question how do i hook up the ballast resistor on a grain truck ? we melted some wiring and i am trying to hook it up so it wont
burn the points up. on about 69 chevy two ton.

Owen Aaland · Jul 27, 2015

It needs to be connected between the ignition switch and the distributor. There should also be a resistor bypass wire coming from the starter solenoid that connects to the side of the resistor with the wire going to the distributor.

stonerock · Jul 27, 2015

bat wire to resistor from resistor to + side of coil - side to dist

mj · Jul 27, 2015

As [b:646c5d0084]stonerock[/b:646c5d0084] and [b:646c5d0084]Owen Aaland[/b:646c5d0084] said AND -
the 'bypass' wire goes to the 'start' terminal on the ignition switch or starter and gives full battery voltage to the coil when starting as it 'bypasses' the ballast resistor.

Steve@Advance · Jul 27, 2015

So how much burned and what was replaced?

The original wiring harness had a resistor wire made into the harness, no external resistor was used. If that wire is still in the harness, don't need a resistor. The way to tell would be to connect the wire to the coil, check the voltage at the coil with the points closed. Should get about 8 to 9 volts. If you get full battery voltage, it will need a 1.8 ohm resistor between the ignition switched wire and the "+" terminal of the coil.

Then, if you want to add a resistor bypass, connect a wire from the "+" terminal of the coil to the "R" terminal on the starter solenoid.

Owen Aaland · Jul 27, 2015

(quoted from post at 21:20:24 07/27/15)

As [b:75ee6c5d8c]stonerock[/b:75ee6c5d8c] and [b:75ee6c5d8c]Owen Aaland[/b:75ee6c5d8c] said AND -
the 'bypass' wire goes to the 'start' terminal on the ignition switch or starter and gives full battery voltage to the coil when starting as it 'bypasses' the ballast resistor.

If you wire it this way you will be feeding the start circuit with power through the resistor when the key switch is in the on position. It could well be enough voltage to keep the starter from disengaging.

Russ from MN · Jul 27, 2015

Doesn't the bypass wire need a diode to prevent backfeed to the starter solenoid?

old · Jul 27, 2015

No it is built into the ignition circuit. In the start position it bypasses but once you drop it to the run position it is no longer in the circuit

vscummins · Jul 28, 2015

Thanks for the replies guys right now I'm just sending battery voltage to the coil when I try to hook up the resistor in the circuit it gets super pretty fast I didn't Leave it in very long but I tested and it dropped voltage from 12 to 10

ballast resistor

vscummins

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Owen Aaland

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stonerock

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mj

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Steve@Advance

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Owen Aaland

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Russ from MN

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old

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vscummins

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