4 Prong Ballast Resistor

Dan The Man · Mar 9, 2021

The 2 connectors, one has 2 wires and other has 3 wires. The resistor has a 5 ohm and 1.2 ohm side. Lets say the 5 ohm is on the top. Where do the connectors go? Or can I eliminate the ballast all together and put jumper wires across these connectors?

Badvert65 · Mar 9, 2021

The factory plugs have a 'locating pin molded into them. This pin (round tab) fits in a hole next to one set of pins and a slot next to the other set of pins.

Dan The Man · Mar 9, 2021

Badvert65 said:
The factory plugs have a 'locating pin molded into them. This pin (round tab) fits in a hole next to one set of pins and a slot next to the other set of pins.

Yea but they can still be reversed if you want. I think I have it right now.

Nacho-RT74 · Mar 9, 2021

if pins are untouched, you can just plug them in one position. That's the purpouse for the pin being sure the correct resitor value goes to the correct destiny. They can be installed on either side but no reversed.

What's your question now? do you want to run some ignition system which doesn't need the ballast ? Several methods to make that:

-splice all wires together ( but the green with red trace, that's just needed for the stock 5 pins Module )
-jumper wire between primary resistor ends. This will make to remain harness untouched, but a wire visible making the job
-remove resistor from the rear groove and replace it with a wire reusing the ballast terminals. This is the cleaner way keeping the stock look, and easy to get it back to stock module ( if needed or wished ) just replacing the ballast for a new one... or reinstalling the resistor if you care. Easier just replace the resistor into the rear groove, being available everywhere.

moparedtn · Mar 9, 2021

Pictures would help this immensely...

Nacho-RT74 · Mar 9, 2021

stock look... visible pin just allows you to plug it in one position... either side. This is to be sure it won't be reversed and the correct voltage will arrive correctly to the Module and Coil.

green wire traced red not used/needed on stock 4 pins modules &/or aftermarket ignition systems

SO if the deal is splice all wires together, that wire won't need to be spliced, but taken appart... neither the jumper blue wire into the other plug, just one blue with the dual brown wire

Nacho-RT74 · Mar 9, 2021

Next... bypass resistor with a jumper wire on the primary resistor path

the ugly procedure:

the "cleaner" procedure ( but still those split terminals exposed are not safe IMHO )

The CLEANEST procedure

Doesn't need to be modified on both grooves, just primary is enough... but as your wish.

THEN better seall the back of terminals with epoxy for safety

Dan The Man · Mar 9, 2021

Nacho-RT74 said:
stock look... visible pin just allows you to plug it in one position... either side. This is to be sure it won't be reversed and the correct voltage will arrive correctly to the Module and Coil.

green wire traced red not used/needed on stock 4 pins modules &/or aftermarket ignition systems

SO if the deal is splice all wires together, that wire won't need to be spliced, but taken appart... neither the jumper blue wire into the other plug, just one blue with the dual brown wire

View attachment 1081142 View attachment 1081143

OK so in your pics is the 5 ohms on the top or bottom??

Nacho-RT74 · Mar 9, 2021

5 ohms resistor is where the green with red trace wire connects

Dan The Man · Mar 9, 2021

Nacho-RT74 said:
5 ohms resistor is where the green with red trace wire connects

View attachment 1081195

Perfect! Got it! Thanks

XS22J8R · May 29, 2023

Which wiring harness is it that has the plugs that plug into the 4 prong ballast resistor?
I thought maybe the engine harness but pictures of engine harnesses don’t have those plugs.
My car has been dogged by an intermittent starting issue that I suspect ties in with this wiring. I’m really dense with electrical issues, I can replace and clean things that’s it.
Car now turns over but won’t eventually start. I was thinking of replacing this harness if I can find one, before I give up and search for a shop that can fix this problem.

451Mopar · May 30, 2023

The 5-Ohm is used for the factory ignition module that has all 5-pins. The 4-pin module has the resistor mounted inside the ECU, so the 5-ohn side does nothing if using a 4-pin ECU.
The 1.2 ohm is the ignition coil ballast resistor.

4 Prong Ballast Resistor

Dan The Man

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Badvert65

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Dan The Man

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Nacho-RT74

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moparedtn

I got your Staff Member riiiight heeeere...

Nacho-RT74

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Nacho-RT74

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Dan The Man

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Dan The Man

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