4 prong ballast with electric choke

[SlinktRR]

my car now has an m&H harness with leads for the 4 prong ballast resistor. So i have the stock 4 prong with a Mopar chrome box, and it works great with a firecore dist and blaster 2 coil. The harness is great, everything works again.. even the clock on the tic toc tach, which i was surprised by. However, i plan to run deeper into the cold weather this year and need to hook the aftermarket electric choke back up for faster starts.

Can i splice off one or both of the 12v side of the resistor or somewhere else? Also, anyone know what the significance of the 4 prong is vs. the 2? Should i just cut the m&h connectors and go back to a 2 prong?

 

[Ranger16]

The 4 prong was used with the 5 wire ECU.
The 2 prong is used after they went to the 4 wire.
https://www.forbbodiesonly.com/mopa...rpose-of-a-four-prong-ballast-resistor.53415/

You should be able to splice off of any 12v source (with ignition on only). I see no reason why the "run" side of the ballast should not work.

 

[Nacho-RT74]

Factory made it straight from the blue ign 1 power line. Since it seems you got a 70 and should get a blue field wire to the alt, you can get it from that line down the harness tape to make a short line wire. On 73 and lates it was made on that way to feed the electric choke control unit mounted on one of the intake manifold bolts

 

[SlinktRR]

Thanks, so if I have this correct...if I'm using the chrome ECU, it is 4 wire ECU and if the engine harness uses a 4 prong ballast resistor connection, then only one 12V lead to that ballast resistor will be hot and the other lead will be 0V.

For the choke I should splice the blue field wire on the alternator which would be 12+V, similar to the ballast resistor feed... but will not be in the ECU circuit.

 

[moes]

we usually run the power for the choke off the wiper motor connector from the bulkhead, that line has a fuse in it already.

 

[Nacho-RT74]

we usually run the power for the choke off the wiper motor connector from the bulkhead, that line has a fuse in it already.

no need for that.

Thanks, so if I have this correct...if I'm using the chrome ECU, it is 4 wire ECU and if the engine harness uses a 4 prong ballast resistor connection, then only one 12V lead to that ballast resistor will be hot and the other lead will be 0V.

For the choke I should splice the blue field wire on the alternator which would be 12+V, similar to the ballast resistor feed... but will not be in the ECU circuit.

don't overthink that. Just splice it from the blue wire wherever on engine harness and done.

ballast is allways hot on both sides, at diff voltage rates depending on the ign switch stage, but allways hot

 

[SlinktRR]

Thank you Nacho, blue field sounds like a good power source I'll tie into there.

 

[Nacho-RT74]

this is what factory made on 73 and lates ( 73 diagram ilustrated ) I made this diagram long time ago.

Engine harness got the provision set for the choke control unit on the run up to the alt brush

 

[Nacho-RT74]

to feed this setup:

 

[idrivemopar]

Who knows how to test the choke control switch? Should it always have continuity between the two spade connectors?

 

[Nacho-RT74]

I think FSM says how, but I don't have it in hands

 

[idrivemopar]

I found it just after I posted my question.