Pos or Neg ground
Fleet Owner
Joined: Jul 2004
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From: NM
I assume this was done by using a 12V generator and regulator? Are you sure it's not just hooked up wrong at the battery?? I can't think why someone would convert to 12v positive ground , if it was already at 12v neg ground???
I think the regulator would be different (maybe not?), and you'd have to re-polarize the generator.
I think the regulator would be different (maybe not?), and you'd have to re-polarize the generator.
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Senior User
Joined: Dec 2005
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Not sure if it was orginally a 6v system, but now that you mention it I believe he did have the battery cables reverse. He mentioned it to me at the time I bought it, but there was so many things he told me and being so excited about getting the truck I forgot. I do have his phone number and will try to get ahold of him to see if he can explain again. Thanks
Matt
Matt
Postmaster
Joined: Dec 1999
Posts: 2,813
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From: Connecticut
When the truck was new, as stated above it was 6 volt pos ground. In 56, Ford changed over to a modern 12 volt neg ground system. Your truck was converted to 12 volts somewhere in it's life. Very common conversion. I doubt it was converted to 12volts pos ground. You can get batteries with the 2 posts reversed to straighten out the crossed cables.
Barry
50 F-1
Barry
50 F-1
Cargo Master
Joined: Sep 2004
Posts: 2,906
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From: Oregon
My fathers 55 is positive ground 12 volt. This is the most common conversion. This done by intalling the reducer in the main 10 ga yellow wire that goes from the solenoid to the battery terminal on the head light switch.. This is the fastest way to convert to 12 volt, just remember to put the battery in pos ground. All the 6 volt trucks were pos ground. All the 56 and newer 12 volt trucks were negative ground. If it was converted without changinf the gauges and electrical, then it should have had a voltage reducer in it, and the battery should be 12v pos ground.
Senior User
Joined: May 2005
Posts: 388
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From: Florida
I've got a similar question along the same topic.. didn't want to create a new thread for it..
My truck in some period of its life was converted to 12v, it has a CD player, thats probably why haha.
So anyway, I am replacing the stock 6v ignition switch with a newer 12v switch.. I bought it from MidFifty, Sy calls me and leaves a message saying that it was originally positive ground and now it will be negative ground.. Need to know how to change the ground from positive to negative in order to have the truck not SHOCK ME when I touch the door!
My truck in some period of its life was converted to 12v, it has a CD player, thats probably why haha.
So anyway, I am replacing the stock 6v ignition switch with a newer 12v switch.. I bought it from MidFifty, Sy calls me and leaves a message saying that it was originally positive ground and now it will be negative ground.. Need to know how to change the ground from positive to negative in order to have the truck not SHOCK ME when I touch the door!
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Junior User
Joined: Nov 2003
Posts: 99
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From: Buckner, KY
12 volt positive ground
I did some searching on this and found this link...but still need answers. My 51 f2 was converted to 12 volts (by the previous owner). I just rebuilt the engine and purchased a new wiring harness and wired her up. She started up and runs great. My question is that the previouis owner wired it up as positive ground and i am not sure why. There is a 12 volt tractor generator on the engine and all the other 12 volt upgrades (solenoid, ballast resistor, voltage regulator, etc.). I am installing the RUNTZ voltage regulators so i can use my stock gauges. Runtz states you must have negative ground to use these. Can i just switch my cables on my battery (take the solenoid battery wire to postive and take the engine block ground wire to negative) and be all set?? Not sure why he would have left it postive ground. Any input??
Thanks ,
Rich
Thanks ,
Rich
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New User
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My 56 is 12 volt positive ground. About 15 years ago, I toyed with the idea of chaniging it to negative ground and was told all I had to do was take one of the wires on the voltage regulator and touch it to one of the posts on the voltage regulator (I think it was the middle post) and that would convert the sytem to negative ground.
I am thinking about doing it again and cant remember what to do. Does this sound right to anyone??
I dont think I am hijacking this thread since the answer will also answer the original post.
Thanks,
Jay
I am thinking about doing it again and cant remember what to do. Does this sound right to anyone??
I dont think I am hijacking this thread since the answer will also answer the original post.
Thanks,
Jay
Elder User
Joined: Aug 2003
Posts: 561
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From: Minneapolis
Jay:
Your 56 was built 12 Volt Negative ground; I don't know why someone would switch it to Positive. Everything else like radio, blower, and wipers (if electric) on your 56 are built for 12 Volt Negative ground. If you want to add anything modern, like a radio/CD, tach, power anything, you will need your 12 Volts to be grounded Negative.
rich51:
Don't attempt to use those Runtz voltage regulators on a Positive ground system; you will ruin them.
In general, I don't trust the work of previous owners. My electrical system (52 F3) was partially converted to 12 Volt negative ground, but still had a 6 Volt generator. Don't assume that someone knew what they were doing or had a good reason to do something that appears strange. We need to figure it out ourselves with help from our friends and this forum.
Your 56 was built 12 Volt Negative ground; I don't know why someone would switch it to Positive. Everything else like radio, blower, and wipers (if electric) on your 56 are built for 12 Volt Negative ground. If you want to add anything modern, like a radio/CD, tach, power anything, you will need your 12 Volts to be grounded Negative.
rich51:
Don't attempt to use those Runtz voltage regulators on a Positive ground system; you will ruin them.
In general, I don't trust the work of previous owners. My electrical system (52 F3) was partially converted to 12 Volt negative ground, but still had a 6 Volt generator. Don't assume that someone knew what they were doing or had a good reason to do something that appears strange. We need to figure it out ourselves with help from our friends and this forum.
Junior User
Joined: Nov 2003
Posts: 99
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From: Buckner, KY
SteV8e,
Thanks for the input. I switched my wires as described in the previous thread and everything seems to be good. Not sure why the previous owner did this...maybe just lazy or did not know. Anyway....thanks again.
Rich
Thanks for the input. I switched my wires as described in the previous thread and everything seems to be good. Not sure why the previous owner did this...maybe just lazy or did not know. Anyway....thanks again.
Rich
Junior User
Joined: Nov 2003
Posts: 99
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From: Buckner, KY
hi...I converted my truck from 12 volt positive ground to negative ground as described above. I started it up today and it started and ran but the generator began smoking??? As soon as i noticed i stopped the engine. As stated above the previous owner converted it from 6 volts to 12 volts positive ground. I switched the wires going to the battery and made it 12 volts negative. I have heard that you have to polarize a generator? Is this true or should i have done this? there is more info above from my previous entries. Let me know what you think or if i need to put down more information.
Thanks
Rich
Thanks
Rich
Junior User
Joined: Nov 2003
Posts: 99
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From: Buckner, KY
Generator polarize
Well I took my generator to a small alternator shop in town and they told me this. When going from positive ground to negative ground you must polarize the generator and regulator.
"To polarize, connect the FIELD, ARMATURE, and BATTERY leads to the regulator. Connect the battery. Then, momentarily connect a jumper wire between the ARMATURE terminal and the BATTERY terminal at the regulator."
Wish I would have know this before. I also fried the contacts on my regulator. Anyway I got a new regulator today and I am supposed to get my generator back next week. Just thought I would post in case someone runs into this. Hate for someone to have to spend money like i did because of a stupid mistake.
Thanks..
Rich
"To polarize, connect the FIELD, ARMATURE, and BATTERY leads to the regulator. Connect the battery. Then, momentarily connect a jumper wire between the ARMATURE terminal and the BATTERY terminal at the regulator."
Wish I would have know this before. I also fried the contacts on my regulator. Anyway I got a new regulator today and I am supposed to get my generator back next week. Just thought I would post in case someone runs into this. Hate for someone to have to spend money like i did because of a stupid mistake.
Thanks..
Rich
Fleet Owner
Joined: Jul 2004
Posts: 27,288
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From: NM
Well, maybe you should have them do it. These are the instructions for Flathead Fords from what I would consider an expert:
"After installing a new generator/regulator, before connecting any wires to the regulator, use a jumper wire and connect one end to the armature 'A' terminal on the generator, then MOMENTARILY touch the other end of the jumper to any 'hot' wire or terminal (battery negative post on positive ground system). Just 'flash' the connection. This needs to be done anytime either the generator or regulator are replaced. If it wasn't done, it's likely that your regulator has been damaged and will need to be replaced... "
(Note that this was written for a pos. ground system - "hot" would be Pos. on yours) From what I recall, if you do it with the wires connected to the reg, you may fry the points. My 49-52 manual is quiet on the subject...
"After installing a new generator/regulator, before connecting any wires to the regulator, use a jumper wire and connect one end to the armature 'A' terminal on the generator, then MOMENTARILY touch the other end of the jumper to any 'hot' wire or terminal (battery negative post on positive ground system). Just 'flash' the connection. This needs to be done anytime either the generator or regulator are replaced. If it wasn't done, it's likely that your regulator has been damaged and will need to be replaced... "
(Note that this was written for a pos. ground system - "hot" would be Pos. on yours) From what I recall, if you do it with the wires connected to the reg, you may fry the points. My 49-52 manual is quiet on the subject...