How the Ballast Resistor Works 

It's amazing how a well drawn diagram and good communication skills can easily trump CGI animations so often.

By far the best explanation I've ever seen on this topic. Well done, sir.

Awesome! Somebody finally took the time to explain the "why" not just the set-up & routing of these wires, but why it is wired this way. This is very helpful in diagnosing a no spark situation. Thank you for taking the time to make this video.

Great pictures, great description. Not 1 in 100 videos is so clear. I don't know why people have such a hard time communicating, but I am glad you are one of the rare ones who knows how to do it. Thanks!

Thankyou. I've only been working on old cars for 60 years and this is the first time I have understood what a "Ballast resister" does! Got it.......at last. I can now die in peace with the question answered, "What's that thing?" on my car! ):

Very well explained, simple but concise, it's about time someone did it properly, it's helped me, thank you

Thank you for explaining how the coil voltage stay the same in crank and run situations. You made it very simple and easy to understand the circuitry.. well done

Perfect, answered all my questions... How to test, typically ohm reading, potential problems. Thanks for the video!

Great video. I've worked on Mopars all my life and knew that a ballast resistor was critical, but never really understood why. Thanks!

I am very impressed with your performance in this video. Direct and to the point that what people want when they are looking for help on youtube auto video's. Well explained and demonstrated. You show what the problem's could be and what to look for. It really help the viewer diagnosing their problems. I learned some things here thank you. Good Job

all comes flooding back. super simple, perfect explanation. awesome mate. thankyou

Thanks for sharing this video. I have to replace my ignition switch on my old Massey Ferguson tractor. This video was just what I needed. Thanks a lot! !!

A very simple and clear description on the function of a Ballast Resister

Awesome job, thank you for the simple yet informative explanation.

Great video. You've covered all sides of the ballast resistor what its for and when its bypassed

More of this guy, please. Really excellent video.

Great illustration! Great concise explanation! Nice, straight and fundamental information!

Thanks man! The tutorial helped me get my 73 mustang 351 CJ back on the road. Needed to add the resistor to the electronic IGto make it work right! 😅👍🏾🐎😎

Excellent work man. Just the information i needed. I'm jury rigging a 6 volt horn to work with a 12 volt system using a ballast resistor to compensate for the extra voltage/amps.

Thank you for this explanation. You have saved me quite a bit of time diagnosing an old Bronco.

Just saw your video ,thank you for helping a 76 year old vet

Thanks so much! Fantastic explanations. My buddy is a mechanic and shared this with me for use with my boat: A 1989 Ski Nautique 2001 inboard with a Ford Winchester Pleasure Craft Marine 351 motor. I’ve been having issues with my motor starting (even with the ignition switch and key turned off) whenever I connect my battery cables. Seems like my Solenoid has maybe gone bad, but gosh your breakdown of the entire ignition chain is so informative I feel much more confident in tracking down the faulty part or cable (like you said, could be something crimped or chewed on by a mouse etc. 😅) Many thanks my friend. You are an amazing resource of information and knowledge. Will be sure to share your content with friends. 😁👍

Excellent, easy to understand. Thank you!!!!

This guy is one of the few people that actually explains the what a ballast resistor really does! Great video!

Great Explanation! Thank you. It fixed my tractor.

Thank you! Best explanation so far.

Awesome! Very well explained. Finally I understood the "I" of the started solenoid.

Thank you very much! I have an older Ford and this helped me out tramendously!!!

Outstanding explanation. Thank you for taking the time to share this.

The best explanation I've ever seen on resistors. Thank You

Great tutorial, helped understand the reason I have a ballast resistor on my TR7 which now runs a 12 volt coil in place of the original 6 volt coil.

Excellent!! Exactly what I needed. Thanks for putting this together!

Thank you....this helped me so much

Excellent video. Thanks for sharing.

Excellent video...perfectly explained and great diagram...well done!

Wow. Thank you. I am a newbie and really really appreciate this as I am troubleshooting an old GMC truck.

Outstanding job. I worked as a technical educator for 5 years, then 29 years in automotive manufacturing, part of that time developing service training for distributor and fleet customer service technicians. I am not a mechanic though, but, I recognize good tutorials when I see them (an all too rare occurrence). There is a need (unanswered demand) for no-nonsense training manuals and audiovisuals for the vintage car owner/enthusiast (non-mechanics, myself included), on early Ford, 6 volt generator, positive ground electrical systems. Actually, vintage car professional (?) mechanics could use it as well. Specifically the battery/generator/voltage regulator (control box as it was called in certain publications)/starter/coil and related wiring, resistors, etc.. You wouldn’t get rich but you might break even and just think of the fun you’d have!

I've watched > 12 videos before this one Finally explained the "why".

Dude! This was the best damned video I've ever seen explaining what happens at ignition and why there are ballast resistors. I am working on my Ford 640 and replaced the ignition switch was seemingly malfunctioning intermittently. When I pulled the hood to get at the tiny block terminal, I noticed that there was a resistor under the dash wired through the terminal block. This Tractor had a 12v conversion done to it long before I owned it, so I figured it was unnecessary and might cause a weak spark so I disconnected it (and installed a new coil requiring, supposedly, no external resistor) and rebuilt the distributor and put in a new condenser and points). When I tried to start it after all of that, it would not start at all. Since I know it had spark before I disconnected the resistor, I figured that ballast resistor must somehow be in the ignition circuit, so I reconnected it and it fired right up. QUESTION: The new coil says it does not need an external resistor, which I take to mean that it has an internal resistor. Does this make the coil more in the 6v range and is that okay for the points and spark? If not, how do I bypass the external resistor? I've seen a lot of comments referencing the 12v coils burning too hot for the points, but does this matter at all? By the way, it purrs like a kitten and all four cylinders have a good spark - I tested them all. Shocking how good this 1957 tractor runs despite the general abuse it has taken over the years. Anyway - thanks for the video. This was terrific help.

Excellent job explaining this. Thank you for taking the time to share this information.

Fantastic!! My 62 Chrysler THANKS YOU!! Just make sure when engine shuts down like he said, dont assume it is the ballast, check wire harness wires could be broken or just not fully pushed into the fire wall or contacts need cleaning. This was my problem and it took a while to figure out. Follow the power like he said you will find low voltage or no power and that tells you where the problem lies. This really helped and I liked the screwdriver pointer Awsome!! My 62 chrysler thanks you !!

Hey Dude, This is a really good explanation of the system! Thank You. I will use every bit of your video to check out my 77 Chevy LUV and get all wires corrected.

Thanks very much for taking the time to explain mate 👍 much appreciated from New Zealand

Excellent video. Thank you!

Thank you.... simple and direct.... thank you

May 3rd-2021, that was pretty damn good, thanks for sharing your knowledge with us

This os the best explanation I have seen

Excellent explanation.

Best explanation I've seen. Great job!

You are the MAN! this is the explanation i've been looking for. I am switching to an electronic ignition in my 66 mustang and have to bypass the resistor. Thank you.

At first, I was here for the eye candies. I am glad I subscribed cause this is very good information with clear simple presentation. Now only if I can convenience Scanner Danner, New Level Auto, Eric O. to do the same with eye candies.

Thank you. You are a great teacher

Thank you so much for this. I have an old Jeep and this info. is exactly what I was looking for, great explanations too.

Thank you, with your info l was able to get my ford truck running right again. God bless.

Great info !!!! I have car with bad start. My garage said pull plus from battery to coil directly to test. I did this but luckily didn’t fry the coil.

Hey man....Thanks for the really cool video. I like the way you explain things. Your video really set me straight on the ignition system. Thanks....

Thank You! A great explanation that totally makes sense! Love it! Peace from New Zealand :)

Absolutely the best explanation I’ve found let !

Great tutorial mate. Easy to understand and made a lot of sense for me to hook up the new wiring harness of my customer's Mustang. Cheers

Good stuff man, I bought a 66 Fury and when I started going through it I noticed that they had electrical tape around a fuse. As it turned out they used that fuse as a bypass of the ballast resitor. Granted, they installed an MSD distributor with an MSD Blaster 3 coil, however, the coil does not need 12 volts going through it. I couldn't find the clue until I watched your video.

Good stuff man! Thank you very much, a great help.

Thank you so much. I've been trying to find this answer for awhile.

Great video. Very well explained!!

Very good explanation, Thank you.

Great tutorial. Pictures are worth a 1000 words.

Great job Sir!!

Amazing video, very well explained thank you’

Great video. Very explained and good art work

Thanks for the video very well spoken and understandable I think that's what's wrong with my 74 duster we going to try that today and see if we can get it to fire up

Yes, very good video, thanks for taking the time to make it !

Best explanation I've seen. Thank you!

Thankyou . great video very well explained

Very clear explanation well done!

Thanks! Very simple!

Thanks. Really helpful

Great explanation! Thanks!

THANKS. After I washed my engine of my 56 Tbird when I tried to start it it would die as soon as the starter shut off. A mechanic told me my carb was the problem. After many hours of diagnosing this and that and finding everything in working order, I finally noticed that a wire had come loose that was connected to my coil resistor and as soon as I hooked it up it started and ran just fine. Sorry I didn't see this video sooner it would have saved me all the time of trying to figure out what the problem was.

My '47 Ford, with original flathead V8, was converted to 12 volt system but still runs the original 6v ignition coil. 2 ballast resistors for this setup!

Thank you soooooo much!!!

Very good presentation, l did not understand this system. Now I do.

Awesome video- thankyou

Excellent video. thank you

excellent video!

Very helpful, thank you!

Great video🤙

Exactly what I needed to know. Thanks

I had a old civic with contact breaker points. The points burnt every two months or so. I got tired of sand paper ritual. Then, someone suggested the resistor and that solved the problem. I never damaged the coil in the 5 years I drove that thing. In another another car, I damaged a few ignition switches when I tried to not used the FORD solenoid. It appears that the current for the starter mounted solenoid was too much for the ignition switch. It looked like that FORD system uses the solenoid as a relay for the other solenoid. I never liked the direct connection of positive cable in old chevrolets. Great explanation!

Thanks for clairifying this!

Thanks for explaining this.

Very cool videos. Thank you. 😎 😎 😎 😎 😎

Great informative video. thank you

Excellent video!

fantastic video...........very helpful............

Excellent !

great explanation.thanks

Nice and simply exclaimed 👍😀

Super vid!!

Like everyone else has said, this is really well explained, thanks!

Great video.

Mate superb! Thank you