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Article Comments
Comments for Step by Step 12V Conversion
Add to these Comments

Ralph Fetter wrote on Friday, June 30, 2000 (PDT):
  • Can this wireing diagram be used for a Super A conversion
    Charlie Webb wrote on Friday, June 30, 2000 (PDT):
  • I want to know if this can 12V conversion also applies or will work on an Allis Chalmers model B ????? I sure did enjoy reading this informative artical keep up good work. C. Webb, Tallahassee Fl.
    The Red wrote on Saturday, July 01, 2000 (PDT):
  • Great article Bob! It is a frequently asked question and I am glad you laid it out step by step.
    Lou Kocon Jr. wrote on Saturday, July 01, 2000 (PDT):
  • Great article which leaves nothing for you to fiqure out. It's all there! As I have a few Farmalls that will benefit from this conversion, I will be making it in the near future on at least one or two of them. How about an article on doing the same conversion on a 3000 Ford, one that also leaves nothing for you to figure out for yourself? Once again, Great article!!!
    Tim W wrote on Saturday, July 01, 2000 (PDT):
  • Thanks for a great article that takes the mystery out of the conversion. Tim
    TERRY KOSER wrote on Sunday, July 02, 2000 (PDT):
  • Great article!! I did this conversion about 8 years ago to my 1939 M,and it still woks to perfection today..again, job well done!!!
    IHank wrote on Sunday, July 02, 2000 (PDT):
  • Good job here! I did this in the early 70's for my 8N Ford and never after did I have to mess with the starter. Before I did, I'd have to replace the starter drive each winter. I recommend you include reversing the coil primary connections, so's the secondary polarity is the proper negative at the spark plug center electrode.
    Brandon Peters wrote on Sunday, July 02, 2000 (PDT):
  • We did this a few years ago to our AC WD-45 and my Super M. We have 2 other WD's that need it. Great diagram.
    Steve Powers wrote on Monday, July 03, 2000 (PDT):
  • I have a Farmall "C". I think this system will work on it as it will on an "M". Am I correct in my assumption? Steve
    Mark Frederick wrote on Monday, July 03, 2000 (PDT):
  • Sounds Good. How close is this to a changeover for a C Farmall, which is what I have. Thanks Mark
    Andy Gallup wrote on Tuesday, July 04, 2000 (PDT):
  • Nice Article! This will be a great reference for converting tractors of other colors as well. Another source for the "no-charge" warning light is Cole Hersee (available where heavy truck parts are sold). They offer a variety of dash mount, 2 wire lamp holders.
    Gordy wrote on Tuesday, July 04, 2000 (PDT):
  • I converted a M John Deere the same way and they now have a Delco 10SI alternator that only uses one wire there for omitting the warning light. Works wonderful! Thanks
    Tom S. wrote on Wednesday, July 05, 2000 (PDT):
  • Good article! However, what if I have a magneto rather than a distributor type ignition?
    Bob Melville wrote on Saturday, July 08, 2000 (PDT):
  • Thanks everyonel for the nice comments!! I've put up a few diagrams and sketches for variations on 12 volt conversions in Photopoint. They cover converting magneto equipped tractors, tractors with solenoids in the starting circuit, etc. Here's the link; albums.photopoint.com/j/AlbumIndex?u=175340&a=1281262 Bob Melville
    Bob Melville wrote on Saturday, July 08, 2000 (PDT):
  • Corrected link for the above (name should not appear at the end); albums.photopoint.com/j/AlbumIndex?u=175340&a=1281262
    Bobby Dietrich wrote on Saturday, July 08, 2000 (PDT):
    David Brandes wrote on Sunday, July 09, 2000 (PDT):
  • Very good article. If you use a fuseable link at the hot wire where you hook it to the starter, if the wire shorts out, it will burn the fuse and not the wire-preventing a fire
    mm wrote on Monday, July 10, 2000 (PDT):
  • The early GM products were wired the same way. Later they installed a resistor in shunt across the idiot light bulb. this would let the alternator keep working even if the ligt bulb burns out.I think it was 20 ohms, 10 watta resistor. can anyone back me up on this ?
    Kenneth wrote on Monday, July 10, 2000 (PDT):
  • Very nice article and diagram. There are a couple of other options with the 10si alternator, you can use a "self exciting" voltage regulator in the 10si and just run one wire off the back of the alternator. You can also use a 10si self exciting Positive ground alternator as well, or even a 6 volt self exciting 10si alternator in pos. or neg. ground. As you can see there are many options with the 10si alternator. Thanks, Kenneth
    Bob Melville wrote on Tuesday, July 11, 2000 (PDT):
  • For "mm"; You are correct! Later GM cars with the 10 SI alternator have a resistor wired in parallel with the warning lamp so the alternator will continue to work if the lamp burns out. Don't know what the resistor was rated, but 20 ohms and 10 watts sounds about right...
    BILLY MARR wrote on Tuesday, July 18, 2000 (PDT):
    Dave Fisher wrote on Thursday, July 27, 2000 (PDT):
  • Enjoyed your 12v conversion article, I am new to the tractor Scene,i would like to know if this conversion will work on an farmall cub with positive ground system, would i have to change starter polarity. thanks
    Bob Melville wrote on Friday, July 28, 2000 (PDT):
  • Dave Fisher; YES - This 12 volt alternator conversion will work fine on a Cub! You will have to connect the battery so it's negatively grounded on account of the alternator, but this will have no effect on the starter. (The starter turns the same direction regardless of ground polarity) Bob Melville
    Myles Ralston wrote on Monday, July 31, 2000 (PDT):
  • I performed this conversion on a 49 Farmall M . I had trouble fitting in the Delco 10si. I wound up using a Mitsubishi alternator from an 89 Ford Festiva being scapped out. The hook up was the same and the size was much smaller allowing it to fit under the hood much easier. So far everything is working great. Thanks for the info on how to do it.
    Tom Schmitz wrote on Tuesday, August 01, 2000 (PDT):
  • Great article, My question is how does a fuel gauge function by reversing the polarity. Does anyone have any ideas?
    Dave F. wrote on Wednesday, August 02, 2000 (PDT):
  • Thanks for the info. !!!! I've been wanting to ddo this for some time.
    ALFRED ERICKSON wrote on Thursday, August 03, 2000 (PDT):
    Mark wrote on Sunday, September 03, 2000 (PDT):
  • Bob, I just finished using your schematic on a Super C Farmall. Worked great. How can I incorporate a voltmeter and tachameter into this system now? What kind of tach would be the most accurate because of the low rpm's involved? Thanks for your help. Mark
    Marv Brannon wrote on Friday, September 08, 2000 (PDT):
  • This is a Great article. I wired my H like From Bobs schematic. I am very happy with the starting and running of the Tractor. The alternator is tight, but I made a bracket and got it to fit fine.
    Bean wrote on Tuesday, September 12, 2000 (PDT):
  • Can you tell me why I had to switch the wires around on the alt. 1 and 2.to make it work right? with out the switch was hot and the tractor would'nt shut off thanks
    Eddie wrote on Friday, September 15, 2000 (PDT):
  • I think you may have saved me alot of time. Very easy to understand article Thank You
    gary green wrote on Monday, October 09, 2000 (PDT):
  • I have got an h and am converting it to 12 volt.My question is how or what do you do with the starter if it has got a mechanical by the foot starter.How or what solenoid do I purchase to make the starter startby a buttoninstead of taking your foot to engage thesolenoid., Agood friend of mine got me started onthese projects.he has a M converting it .He says he had to purchase a field relay to make his work.Why did he have to do that. As you can probably see Ijust came in from the shop.Hope to hear from somebody so I can finish this soon.All the old guys that use tobe around are not around to help any more.*I used to go up town and just come back with the parts and knowledge.
    Dan W wrote on Monday, October 23, 2000 (PDT):
  • Really enjoyed your article. used it to convert my SMTA and worked great. Had converted a JD430 before but used a 12 volt coil with internal resister and was more expensive. I used the old generator bracket but turned upside down, drilled the hole to 3/8 and put a 1/2 inch nut on the front for a spacer. With a 35 inch belt it worked great. On my tractor the upper part of the thermostat housing had a flat spot on the front with some "meat" to it so I drilled and tapped for a 5/16 bolt and used the old adjuster but cut the outer hole out a bit to give some movement. Only other thing is my local wrecking yard wanted $35 for alternater but guess that is what happens in a small town. Anyway was grat article and I have copy for my tractor book. I am new to IH but learning fast with the SMTA Dan
    Big Baer wrote on Tuesday, December 19, 2000 (PST):
  • Thanks Bob for the instruction on the 12v conversion
    stevie-b wrote on Saturday, February 03, 2001 (PST):
  • Daniel; I have been there and done that also. Iused to blame Freddies gas for the fouled plugs and rough running engines. On my M I instaaled a new 12 volt coil and an any q uestion? electronic igniter. After adjusting valves and timming I have one smooth running M. Have come to the conclusion that you need a good coil. Have replaced coils in two other tractors also. Swithching to a 12 volt system and installing a new 12 volt coil sure makes a differece.
    Dick Davis wrote on Thursday, March 01, 2001 (PST):
  • Great- Straight forward, easy to understand, detailed. Don't plan on doing this but have printed a hard copy and will save in my library. Thanks very much. D-2
    Barry Ross wrote on Saturday, March 17, 2001 (PST):
  • Good article. What I would suggest is to change the old 30 amp ammeters to the modern 60 amp or greater.
    Red Rider in PA wrote on Saturday, April 07, 2001 (PDT):
  • You don't happen to have similar instructions for a 6V to 12V conversion using a generator do you? Thanks for this valuable piece of information.
    Kevin wrote on Friday, August 31, 2001 (PDT):
  • Bob, Would you please get Photopoint to correct their problem with the your schematic diagrams? They will not load, they mention some kind of error.
    BOB wrote on Friday, October 05, 2001 (PDT):
  • can i get aschematic for 12vol while useing a mag. i only need batt. for starting. i have no lights or accessories.
    carlos r newsome wrote on Sunday, February 24, 2002 (PST):
  • thanxs for this info i wish i could have found this just a little sooner and it my have saved one delco alterator thanx again and hope to find my more answers when i need help again carlos
    Ralph B wrote on Wednesday, June 19, 2002 (PDT):
  • Can I assume Knowing how assume is spelled that this would work on the Ferguson Model 20's?
    Frank Lupinski wrote on Monday, July 29, 2002 (PDT):
  • Will this same conversion work on an IH 350? Looks Like it will. Frank
    dave mcclain wrote on Sunday, October 20, 2002 (PDT):
  • will this conversion on a farmall m work the same on the cub?
    douglas hulme wrote on Thursday, November 14, 2002 (PST):
  • Bob thanks for posting the diagram and specs for the 12 volt conversion. WE used it on our 56 Farmall 300. Works like a champ. Much appreciated.
    vince jarabeck wrote on Tuesday, December 24, 2002 (PST):
  • First, all instructions are very helpful and well done, however my conversion project on a TO-30 has me a little baffled. The ignition switch also contains the light switch. Does the ignition then require a jump wire from the ammeter to power both the ignition and lighting? And if so, what gauge wire should be used there? Thanks again, for getting me this far....
    Brent Glaser wrote on Saturday, January 25, 2003 (PST):
  • I'm not an engineer, but, I'm sure the alternator will work best without the "idiot" light AND you do not need a resistor of "I don't know" ohms or current value. The alternator is just an electromagnet spinning inside a coil of wires. This electromagnet is energized by the small difference in voltage between the BATTERY voltage and the voltage in the ACCESSORY circuits (hooked up to terminals #1 and #2 of the alternator, and I don't think it really matters which is which since the diodes rectify the AC to DC. A resistor in the ACCESSORY line will reduce the voltage perceived at the alternator, possibly causing an overvoltage/overcharging situation=boiled batteries and burned out lightbulbs (which is why you are always better of with a voltmeter, not an ammeter.
    Brent Glaser wrote on Saturday, January 25, 2003 (PST):
  • Also, once the engine is running and the alternator is energized, won't that keep 12 volts going to the ignition coil? (This means it won't shut off with a simple toggle switch}. You really need a generic key type switch with separate IGNITION and ACCESSORY terminals, or use the newer "one wire self exciting alternators" if you want to stick to the race car toggle switch run/kill plus push button start simplicity. I've tried the way the schematic is drawn, and it won't shut off, unless it is a diesel.
    Buddy Vail wrote on Wednesday, March 19, 2003 (PST):
  • It seems to me this ought to work on my 200 Farmall. It has been somewhat converted, it has an alternator but it's not charging the battery, according to the wiring diagram in this article it's not wired correctly. So, will this method work on my 200?
    Bob M wrote on Saturday, March 22, 2003 (PST):
  • This circuit will work fine on your 200. Only change would be if it has a key ignition switch w/solenoid in the starter circuit. A diagram for this setup can be found in the collection here; albums.photo.epson.com/j/AlbumIndex?u=4001561&a=30065733&f=0 ...Bob M
    Wayne wrote on Monday, March 31, 2003 (PST):
  • Using wireing diagram # 8 on a "C". It has a push/pull stop sw on the magneto which I plan on keeping. No starter solenoid, just a positive cable from the battery to the starter. I think I still need a wire from # 1 lug to the ammeter going through a warning light and a SPST switch to get the charging system to work. My Delco alternator has a #1 lug and what appears to be a 0 in the #2 position and has a grounding lug on the back of the case. I will still need a #10 gauge wire from the positive post on the battery to the ammeter. Please let me know if I'm wrong.
    Ted wrote on Saturday, September 27, 2003 (PDT):
  • Great article thank you. Could we see the same for a magneto ignition?
    andy looney wrote on Sunday, September 28, 2003 (PDT):
  • need step by step 12V conversion on a ford 9N
    larry riffe wrote on Tuesday, October 07, 2003 (PDT):
  • hello ,i have not seen the article on 6 to 12 volt conversion.i need a step by step instructions on how to wire 6 to 12 volt, for a 2000 ford tractor, i have the one wire conversion for the alterator and have made the mounting bracket.
    Ken wrote on Sunday, October 12, 2003 (PDT):
  • I want to convert my Farmall Cub 6 volt to a 12 volt system. If I do is there any special instructions for the existing system of reversed polarity + to ground - to hot??
    John de Marrais wrote on Monday, December 08, 2003 (PST):
  • A few comments. Adding a ballast resistor bypass is useful, especially in cold areas. Easiest way to add is to use a Ford type starter relay with the built in bypass via the "I" terminal. Costs about $10 new. By using this, the push button, or ignition switch will not be carrying full starter current and last longer. Without the bypass, the coil may only be getting 9-10 volts when the starter is cranking. For those using Delco alternators and installing into a tractor that does not have an ignition switch, the internal regulator can be replaced with a $15 self-exciting regulator that requires only one wire hook-up, i.e. no ignition switch necessary. Also, for those situations where clearance is a problem with the rather large diameter Delco, the alternators off older Subarus work nicely. Much more compact, just as common and cheap, and hook up is the same. They also have the same size pulley shaft as the Delco and will outlast it. For tractors that are users in the field, and not just show tractors, the standard unsealed Delcos used in cars don't have a very long lifespan in dusty environments. We had a fair amount of trouble with them at the John Deere dealership, mainly from dust chewing up the armateur and brushes. Deere finally switched to sealed units.
    Eric Hesher wrote on Monday, May 10, 2004 (PDT):
  • I just completed the converson and it works great! Your instructions were very clear. I would suggest using a Powertwist adjustable length V-belt to make the assembly easy. Thanks for posting the info.
    Dick A wrote on Sunday, September 12, 2004 (PDT):
  • I tried to "copy and paste" this article, but it would not "paste" the diagram. Could you tell me how to print the whole thing without the other side lines. Thanks This will be saved for posterity.
    T. Wisner wrote on Wednesday, October 13, 2004 (PDT):
  • Hi Great article and usful info.. But one question comes to mind? If you switch from a positive ground 6 vot system to a negative ground system, in theory that starter will then spin in the oposite direction causing many problems such as fwd and rev tranny motion if it indeed starts? any insight to this?
    John Johnson wrote on Sunday, January 23, 2005 (PST):
  • I liked the article very much and was using it to troubleshoot my problems. I was told how to use a single terminal alternator specifically designed for this type of conversion. The local alternator/starter rebuilder shop told me how to run the alternator and ampmeter but not everything else. I bought a new battery and nothing works. I know I have to take the battery and have it tested but do you have any other thoughts that may be keeping the starter from turning over? I had them test the starter while I was there and it was fine.
    Wade wrote on Wednesday, April 27, 2005 (PDT):
  • I dont see the starter switch on the diagram, how should it be wired?
    funkyford wrote on Friday, May 27, 2005 (PDT):
  • come off the run side of the ignition switch to 1 side of the start switch, the other side of the start switch to the starter relay
    John Martiniuk wrote on Sunday, November 06, 2005 (PST):
  • Where can I find that article "step by step 12 V conversion?Thanks
    Jerry McSheffery wrote on Wednesday, November 23, 2005 (PST):
  • Isn't there usually a starter switch/button between the positive battery post and the starter? Diagram doesn't show this. Good article though.
    Joe Riganti wrote on Sunday, February 19, 2006 (PST):
  • I Can not seem to connect to the link albums.photopoint.com/j/AlbumsIndex?u=1753408a=1281262. Any advice?
    Bob Melville wrote on Thursday, March 16, 2006 (PST):
  • Joe - Wiring diagrams and charging system troubleshooting flow charts can now be found here; albums.photo.epson.com/j/AlbumIndex?u=4001561&a=30065733&f=
    loran cooper corvallis oregon wrote on Friday, October 20, 2006 (PDT):
  • can the diigram for wireing be down loaded for safe keeping in my tractor book (my tractor is kubota with an 12SI 105 amp alternator ( it was on a junk yard car)
    Aaron Cranney wrote on Sunday, January 28, 2007 (PST):
  • Thank you for the information. I am applying this conversion to a 1952 JD MT. Any additional guidelines for the JD and these instructions i.e. components I should or shouldn t use Any feedback appreciated.
    lee allen wrote on Wednesday, April 04, 2007 (PDT):
  • Does someone have a 6 to 12 volt conversion diagram. I need the one that uses a 12 volt battery, 12 volt coil, amp meter, 4 post switch, 12 volt starter with selinoid, one wire alt.
    Lowell Dubbels wrote on Sunday, April 29, 2007 (PDT):
  • Good simple description and diagram. I suggest you state what the warning lamp holder and bulb is for.
    Ken Frost wrote on Thursday, July 26, 2007 (PDT):
  • On my VAC 1952 Case, I was told to connect the heavy output wire 8 ga from the alternator to the other side of the ammeter battery side at the starter switch terminal. I also left the idiot lite out of the circuit. Other than that are circuity looks the same. Comments
    ray c. wrote on Wednesday, August 08, 2007 (PDT):
  • cannot seem to open link. albums.photo, etc
    Michael R. Hernan wrote on Saturday, September 01, 2007 (PDT):
  • When wired as shown on a Farmall M the engine will not shut off when you push in the stop switch because the alternator feeds voltage back to the ballast resister, you need a diode in the line #1
    Tony Ricketts wrote on Sunday, September 16, 2007 (PDT):
  • I just have one question. If you reverse the polarity as you describe in this article, does the starter rotation not reverse
    Marty Martenet wrote on Wednesday, December 05, 2007 (PST):
  • If I have a new 10-sI singel post alternator how do I wire? And is there a way to wire system with out using abalace rester? Thanks Marty
    Ray Force wrote on Thursday, February 21, 2008 (PST):
  • Great diagram and I will begin converting our M, but I am still a little confused on the purpose of the warning light, please explain.
    Larry59 wrote on Tuesday, March 18, 2008 (PDT):
  • Really a good article to read and know. Helps with diagrams to. Thanks for posting it.
    tyler pankey wrote on Saturday, October 18, 2008 (PDT):
  • I am coverting my ford jubilee from 6 volt positive ground to 12 volt negative. I have a single phase one wire alternator. Do I connect the wire to the negative side of the battery? what do I do? Do I need to re-wire anything else? Any help would be appreciated
    mike cabe wrote on Sunday, October 19, 2008 (PDT):
  • is this the same 12 volt wireing for the cub also
    Jake wrote on Wednesday, November 26, 2008 (PST):
  • I think you have forgotten one wire on this wiring diagram. I believe there needs to be a wire from the ignition to the started. Otherwise there is nothing to tell the starter to turn on. Jake
    Luke wrote on Sunday, March 22, 2009 (PDT):
  • I saw that another guy asked if a Super C could be converted the same way but was not able to find an answer for that. Could someone assure me? Thanks.
    Albert wrote on Monday, April 06, 2009 (PDT):
  • Hi there it is a very nicely detailed schematics for a farmall super M. The only question i have is in your diagram i was wondering where you put your push button in at ? and if you connect wires to push button or to the stud on starter? Thank you Albert
    David Hill wrote on Monday, September 14, 2009 (PDT):
  • Hi Bob I have a Massey Pony that was converted years ago before I got it. I came across your article and was wondering what the ballast resistor is rated at? I have tried to check mine but either my analog meter is not fine enough to pick it up or some how it is acting like a direct connection and resistance. Any help thought much appreciated. DH
    Gary wrote on Friday, September 25, 2009 (PDT):
  • Ok, I did this to my farmall cub. The only difference was I used a voltage regualtor rather than an ammeter and a coil with a resistor built in. The tractor would not start. I reversed the wires in the voltage regulaor, same thing. When I jumped the terminals on the voltage regulator, it started and shut off normally. why is that?? ANy help would be appreciated.
    Gary wrote on Friday, September 25, 2009 (PDT):
  • Ok, I did this to my farmall cub. The only difference was I used a voltage regualtor rather than an ammeter and a coil with a resistor built in. The tractor would not start. I reversed the wires in the voltage regulaor, same thing. When I jumped the terminals on the voltage regulator, it started and shut off normally. why is that?? ANy help would be appreciated.
    John Hoard wrote on Friday, October 30, 2009 (PDT):
  • I just converted my WD45 Allis per your instructions and it ran great. The instructions were so easy that printed in Graille a blind guy could master the conversion. Thx a Million,,,John
    John H. wrote on Friday, October 30, 2009 (PDT):
  • So no one has explained as how to fix the problem of the engine running even after the toggle switch was turned off. Someone wanna help there?? Thx
    Sammy in Kansas wrote on Friday, March 19, 2010 (PDT):
  • Does anyone have something like this for a mag system? I would sure appreciate it.
    robert wrote on Friday, April 02, 2010 (PDT):
  • could you give me a wiring diagram of a alternator with external regulator? Thanks Robwert
    cutter wrote on Monday, May 17, 2010 (PDT):
  • will this work on a farmall b
    Randy wrote on Sunday, June 27, 2010 (PDT):
  • will this diagram work on a 350 international harvester?, Thank-you.
    John wrote on Friday, August 27, 2010 (PDT):
  • I was wondering if any one has a wiring diagram for a 12volt conversion with magneto. I have a 1947 cub that had been converted before I purchased and it has some shotty wiring. Would like to rewire
    Drew Patterson wrote on Saturday, September 11, 2010 (PDT):
  • Will this basic concept work on other 6 volt tractor systems, say for example a John Deere 420T that runs off propane? Thank you
    Travis wrote on Wednesday, March 23, 2011 (PDT):
  • Thank you very much.
    Frank wrote on Sunday, March 27, 2011 (PDT):
  • Very good. thank you. I will be adding a 30 amp in-line fuse from the alternator as I had that wire short to ground on my 8n Ford and wiring went up in smoke. will put it between battery and the ammeter. Am doing a WD45 now.
    Ricky wrote on Wednesday, April 20, 2011 (PDT):
  • i have a farmall super A wired the same way. It is overcharging the battery. I have taken the alternator to be tested and it checks out good. Can i put a external voltage reg on it? if so What kind, where, and how? Thanks for any info Ricky
    Buster wrote on Sunday, May 01, 2011 (PDT):
  • I have read all of the comments as my conversion will not shut off the engine when the switch is opened. Others have experienced the same problem but no one has answered what is needed to accomplish this. Anyone?
    J. Grant wrote on Sunday, June 12, 2011 (PDT):
  • I am converting an Allis CA to 12 volt and am told the polarity must be changed from pos. ground to negative. Will this cause the starter to run backward?
    Brian Laine wrote on Sunday, October 16, 2011 (PDT):
  • Exellent diagram instead of the warning light I used a push/pull 75 amp switch. It functions the same as a warning light and prevents the altetnator from drawing down the battery. Have done 3 farmall M's and a B all working great. Thanks
    Dave Pierce wrote on Tuesday, October 25, 2011 (PDT):
  • I recently did a conversion from 6 to 12 volt on my M international, but now engine will not shut off by switch or by unhooking the battery. I wired it using the conversion illistration. alternation is s1. advise would be appeciated.
    robert wrote on Monday, November 21, 2011 (PST):
  • i have a 450 farmall, that had a 12 volt generator that was positive ground and i put a alternator on it and wired it like the diagram and turned the battery around so now it is 12 volt neg, but my blast resistor is getting hot just with the battery hook up with out the key on, did i hook up something wrong.
    Joe Bravata II wrote on Wednesday, February 15, 2012 (PST):
  • i have a 1955 Farmall 100. Would the M conversion be the same for my 100? If not could you tell me how to convert my 100 to a 12 v system. Tanks, Joe
    Jim wrote on Thursday, September 06, 2012 (PDT):
  • When I bought my 1950 Case Tractor, the previous owner switched from 6V to 12V. Only HE didn't change everything and I've been fighting this for over two years. Your Article has helped me immensely and I'll be re-wiring this weekend. Thanks Jim
    William Beale wrote on Saturday, December 01, 2012 (PST):
  • Will this wiring also work on a ferrguson to 20 with a 3 wire alternator. 1950 Massy Harris Ferguson. The amp meter was missing when i purchase it but did hase the 12 volt alternator mounted.
    Ronald Mc Bain wrote on Monday, January 13, 2014 (PST):
  • How to keep the battery from draining down do I need a one way resister
    Dan Dettmann wrote on Friday, July 25, 2014 (PDT):
  • Great information but your comment about jump staring a negative ground system may confuse some people. It doesn't matter if the system is negative ground or positive ground, the jumper connections are the same, positive to positive, negative to negative.
    EDthePLUMB3R wrote on Tuesday, March 17, 2015 (PDT):
  • Hello, excellent job on the drawings here. so easy and simple plumber such as myself could figure it out. So I thought... this conversion was done on my farmall m when I acquired it but it was a hack job. so I thought I would rewire it. I followed the specs of above to the letter finish last night trying to start it, nothing. it cranks but it will not turn over. The only two unknown variables that I can figure out are 1- not sure that the factory lights switch works the hack job done previous skiped that. 2- when I started the alternator want just one wire to it. The second smaller return wire was broken half way back and just taped off. I'm a little out of my room here so any help would be very much appreciated. Thanks, EDthePLUMBER
    K. Payne wrote on Saturday, July 11, 2015 (PDT):
  • I have a Farmall MD that my Dad had stored in his shop. My brother caught it on fire while picking corn. The wires are burnt off and I have no idea how to rewire it. Also it has a 12 volt battery in it but the generator belt was off and wired back to the brackets. I'm confused to say the least. Really not sure what had been set up on it or why. My Father is not able to be of assistance. Any help would be appreciated.
    ron green wrote on Tuesday, January 19, 2016 (PST):
  • if I replice the 6v coil with a 12v coil will I still nead the ballast resistor thank you great article
    LHLjzUfi wrote on Wednesday, April 13, 2016 (PDT):
  • Wow, this is in every resepct what I needed to know.
    terry wrote on Saturday, April 16, 2016 (PDT):
  • I hooked every thing up per diagram and the warning light comes on when i shut the tractor off.
    Iven gwinn wrote on Sunday, August 21, 2016 (PDT):
  • Is it the same for a Farmall h
    blackdogcamper wrote on Sunday, August 21, 2016 (PDT):
  • need more like this artical
    Eddy Goulding wrote on Friday, September 09, 2016 (PDT):
  • Will a 1953 farmall cub go wired the same as diagram you have listed thank you
    wendell wrote on Wednesday, October 26, 2016 (PDT):
  • i have a 12 volt generator.they have two wires.i am going from six volt to twelve.how do i wire it up.it is a 1952 massey harris
    Wayne wrote on Wednesday, November 30, 2016 (PST):
  • Do you need that ballast resistor if everything is c.hanged over to 12 volts,on a t-30,1952 ferguson tractor,and can I use that warning light instead of that toggle switch they have wired in so my system when shut off won't drain the battery,that toggle switch keeps braking of in the winter time then you got to take the battery general of every time you shut it off.
    John S. wrote on Monday, July 17, 2017 (PDT):
  • Question, Will this Farmall scheme work on a ford? I know it's a dumb question, but had to ask.
    Merle wrote on Wednesday, August 09, 2017 (PDT):
  • You did a fantastic job writing this article. It's simple to the point and covers all the steps very clearly doing this job. This article came up as the first link when I did a search on converting wiring to 12v on IH M tractor. My brother accidentally rolled over Our M while digging the foundation for his sons house about a year ago. Then while it was running upside down and we were wondering what to do, catching our breath, it caught fire! He's now in the process of getting it working again and instead of replacing the 6 V system, he plans to convert to 12 V. This article will be a tremendous help greatly in that process. Thank you for providing this valuable information.
    Harold been wrote on Sunday, October 11, 2020 (PDT):
  • I bought a IH Super M, guy says he did a 12v conversion, but was unable to figure out the wiring, so when it starts it's running on battery. He left the original starter in and it's real hard to start. He put in a made in china alternator left in original distributor and coil and starter looks original with a manual switch. If I have parts you described for the conversion I feel like I got a great machine and can complete this conversion
    Robert Almstrom wrote on Monday, August 23, 2021 (PDT):
  • 1948 Farmall C 12 volt I have the indicator light one side to amp. meter other side grounded. keep blowing fuses? light does come on. Does the wire go straight through without being grounded? Thank you.
    Randy wrote on Saturday, December 11, 2021 (PST):
  • This is fantastic! A few actual photo’s of the wire connection points on each component would make it Awesome!

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    Today's Featured Article - Grain Threshing in the Early 40's - by Jerry D. Coleman. How many of you can sit there and say that you have plowed with a mule? Well I would say not many, but maybe a few. This story is about the day my Grandfather Brown (true name) decided along with my parents to purchase a new Ford tractor. It wasn't really new except to us. The year was about 1967 and my father found a good used Ford 601 tractor to use on the farm instead of "Bob", our old mule. Now my grandfather had had this mule since the mid 40's and he was getting some age on him. S ... [Read Article]

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