Red hot resistor

[SHX669]

What would cause my ballast resistor to get red hot and quit working?
I've got the DurasparkII ignition module and distributor , MSD BlasterII coil , a virtually new HD voltage reg , and a Painless wiring harness.
I've got the ballast resistor because the Painless doesn't have a resistor wire in the run circuit - and MSD says if you don't have the resistor wire you need the ballast resistor to prevent burning up the coil. - nothing to do with points ignition .
Soo- it wouldn't start , i looked under the hood and the ballast resistor was glowing red . After i let it cool down the engine wouldn't start so i bypassed the resistor and it started and ran . But the coil started getting pretty warm so i shut er down.
What would/could cause that? -- bad -- voltage reg , coil , ignition module , bad resistor , something in the "magnetic pickup" in the dizzy?
I'm going to replace the resistor ; i just didn't want to fry that one too.
SHX
Oh - do they make an internally resited coil - and what would it be ?

 

[Steve83]

WHAT YEAR IS YOUR BRONCO? Put it in your signature &/or profile so it always shows.

Any additional load on the coil circuit (like aftermarket accessories that were miswired to it for key-on power) will cause the resistor to get hotter than it should. In this diagram, NOTHING should be spliced to circuit 262 Br, or to the section of 16 R/Gn between the resistor & the coil.



If you have no splices there, AND 262 Br is connected to the starter relay, try disconnecting it. If the resistor cools down, replace the relay with the newer style.



A coil with higher internal resistance would defeat the purpose of circuit 262, which is to supply the coil with full battery voltage during cranking to give a more-powerful spark, but then reduce power to the coil during running to keep it cooler. You could eliminate the resistor by installing a new-style E-core coil, but that would probably just burn the ignition switch &/or wiring because the fault would still be there. You need to find & fix the fault FIRST.

 

[broncnaz]

Most likely the ballast resistor just failed it happens. Id replace it but you could also have a bad coil that is causing the ballast to overheat.