4 pin vs 5 pin?

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BigBlockMopar28

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Came across a thread on google regarding the 4 pin ecu vs the 5 pin, and something about dual ballast resistors having a different resistance level depending on whether its being used on the primary side or secondary? I've been having issues with wiring up an electronic ign for awhile and i'm wondering if it has something to do with this... currently using a 4 pin box and dual ballast but until today I had no idea about the primary side and such on that ballast, so its untelling what side i've had it hooked to and all. I also have no idea what that 5th pin would be used for, that particular thread didnt make much sense to me, my plug does have the 5th wire. TIA
 
Came across a thread on google regarding the 4 pin ecu vs the 5 pin, and something about dual ballast resistors having a different resistance level depending on whether its being used on the primary side or secondary? I've been having issues with wiring up an electronic ign for awhile and i'm wondering if it has something to do with this... currently using a 4 pin box and dual ballast but until today I had no idea about the primary side and such on that ballast, so its untelling what side i've had it hooked to and all. I also have no idea what that 5th pin would be used for, that particular thread didnt make much sense to me, my plug does have the 5th wire. TIA

Check out some of these results and I bet you find your answer.
BTW, @67Dart273 knows all the specifics of both.

mopar 4 pin ecu wiring - Google Search
 
In a nutshell... The 4 pin ECU can use the single ballast resistor.

The 5 pin used the dual resistor. One side of the resistor (.5 ohms) was used in the starting circuit. You would turn the key to "start" and the electrical current would flow through that side of the resistor. The other side (5 ohms) was used in the run circuit. The car would start, you would release the key and the electrical current now flows through the 5 ohm side.

The 4 pin has no current flowing thought the ballast when the key is in the start position. In the run position, current flows through the 1.2 ohm resistor.

EDIT: corrected resistance value of dual ballast resistor
 
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Here’s the 5 pin circuit from 76 FSM

49F40386-BB5F-4B87-B645-0FAC81C9ABED.jpeg
 
I had no idea about the primary side and such on that ballast, so its untelling what side i've had it hooked to and all.
My resistor has a hole next to each set of terminals and the connectors have a plastic pin that goes into it, so they could be switched left to right, but will always land on the correct side of the resistor.
 
5-pin must use dual ballast
4-pin can use dual ballast
The difference is the 4-pin moved the step-down of the power needed to run the module inside, as it was already getting 12v also.


Alan
 
5-pin must use dual ballast
4-pin can use dual ballast
The difference is the 4-pin moved the step-down of the power needed to run the module inside, as it was already getting 12v also.


Alan

Low voltage side, the .5 ohm.

If you wire it for a 5 pin/dual ballast, you can run either box. i did this way back when on case I broke down and they only had the 5 pin in stock.
If you use an msd box at some point, just bypass the ballast and hook the 12 v side wire to the coil.
 
Low voltage side, the .5 ohm.

If you wire it for a 5 pin/dual ballast, you can run either box. i did this way back when on case I broke down and they only had the 5 pin in stock.
If you use an msd box at some point, just bypass the ballast and hook the 12 v side wire to the coil.
I guess I should have added the word module, 5-pin module must use the dual ballast, so yes with the dual ballast you can use either module.
If you get the 4-wire pigtal you must use a 4-pin module. If the is an upgrade to an older system then no need to change the ballast.


Alan
 
Ok, this makes much more sense now lol. I was using both sides of the dual ballast under the assumption that they both gave an equal amount of resistance, not to mention it was probably wrong in the first place lol. I have the 4 pin and dual, so I only need to be using the primary side, and for coil + in run, correct? Then full 12v start for cranking
 
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