Advantages of dual ballast over single??

[dustoff440]

I am rewiring my Dart and was wondering if there is any advantage to using the dual ballast resistor instead of the single. I was also wondering if I installed a dual and only used on side could I use the other one for a spare if the one side burnt out???

 

[oldkimmer]

...........just use a single........not usually.......kim............

 

[LH23H2R]

the 4-prong ballast resistor was used in factory-installed "Breakerless Ignition" systems from Chrysler .
The ohms are different from top-to-bottom , side-to-side ; both sides still function in a "start" and "run" capacity , just as a 2-prong ( e.g. , breaker point ) ignition .

For reasons of simplicity , the Orange Box ignition conversion includes -- or at least it used to -- the 2-prong ballast for breaker point-to-breakerless ( electronic ) conversions
( e.g. , the 1972 & earlier cars ) ; this is the one I used -- back in 1992 -- for my '72 Dart .

Can you "bypass" the use of the other prongs ? I can't say for certain ; I can only tell you that , on my daily driver 1972 Coronet's factory-installed breakerless ignition ( car was built in June 1972 , just about the time that even the 318 -- and possibly the 225 Slant and the 400 two bbl -- had standard electronic phased-in ) , the 3.5 ohm wire ( the lower connector ; top connector is , iirc , 1.7 ohms ) had worn itself out , broke-away from the harness , and kinda came-off when I last replaced the 'resistor .
I've had no apparent problems with its loss ; car still fires-off with zero problems , and the alternator gauge still sits ( little fluctuation ) where it's supposed to ( no deep discharge / overcharge ) .

Don't know if this is acceptable in the long-term ... Eventually , I'm going to buy a new harness , to replace the nearly forty-years'-old original .

 

[dusterny]

You can use the two bottom prongs and your car will run fine. If you try the top two your car will fire while cranking and when key is let off it will stall out. So it can't be used as a back up ballest resistor. Just use the single resistor.

 

[skykeith]

The dual ballast resistor is for the systems that have the 5 pin ignition module. You'll have to see whether you have a 4 or 5 pin module and wire it accordingly.

 

[67Dart273]

The dual ballast resistor is for the systems that have the 5 pin ignition module. You'll have to see whether you have a 4 or 5 pin module and wire it accordingly.

To simplify further (I hope) the 4 prong ballast MUST be used with a 5 prong ECU

A 4 pin ECU can be used with EITHER a 2 or 4 pin ballast.



The resistance of the two halves is different. One half is same as 2 pin, hooks up to coil as it always did.

Second half of 4 pin resistor is used INTERNALLY in the 5 pin ECU box

 

[Wheel Chock]

The only "adavantage" that I can think of for using a 4 prong ballast is if you really enjoy replacing them. Even when these cars were new, many people learned to carry a spare 4 prong in the glove box. When I was working in dealerships in the 70's, the service writers kept them in their desks and used them to plug into the tow-ins from the weekend on Monday morning so that we could clear the service drive to open.
After Chrysler went to the 4 prong ECU/2 prong ballast combo, about 1978, they got a lot more reliable. On my 75 W200 when it had the 4 prong, if the engine was warm and you opened the hood after a rain or washing the truck, water would drip on the hot ballast and kill it every time.