electrical question

jrandalls · 05-19-2007, 07:09 AM

By no means am I a mechanic so I hope this is not a stupid question. I have a 71 ford f100, my step dad recently got a 71 ford f350. Under the hood the trucks apear to be basically the same except for something that has me puzzled. On my truck the battery is grounded to the engine and the positive side of the battery goes to the starter solenoid and then to the starter. That seems logical to me. On the f350 it is just the opposite. The positive side of the battery goes to the engine block and the negative side goes the solenoid and starter. The stuck seems to operate fine. I would think that one of these trucks is defintly wrong, my question is which one?

mrjohnwayne · 05-19-2007, 08:16 AM

Are you going of the wire color or have you looked at the little marks on the battery to see which side is + and -. You can't always trust the colors. I don't see how the truck would opearte with the wires backwards and the battery not blowing up.

75K30 · 05-19-2007, 09:18 AM

Positive ground.
Guys have never seen that?
Many vehicles used to have a pos. ground. Everything works the same, only instead of grounding the neg., (and it is neg ,-12 VDC and not ground like most people call it), but nothing in the rules of electricity states that the neg has to be the common.
Now if you install an aftermarket radio or something, you, must remember to wire it pos ground. It gets interesting, and sometimes fun, but your eyes are not playing tricks on you, even though I don't remember a 71 using a pos ground, it is entirely possible.

mrjohnwayne · 05-19-2007, 12:03 PM

Never seen a positive ground. Good info though!!

mont91 · 05-20-2007, 07:26 PM

Ford vehicles(maybe not heavy trucks) and tractors went to negetive grounds by '60. Check the post markings, '71 Ford F350s were negative ground. I bet somebody in the past used what ever cables they had.

gmctrucks · 05-24-2007, 02:38 AM

My brothers 41 Ford Deluxe is connected like that but it's wrong because the Amp meter goes down instead of up. But many, many, moons ago they were set up like that my Dad told me he's only 81 years young and doing GREAT.

05-19-2007, 07:09 AM	#1
jrandalls Junior Member Join Date: Mar 2007 Location: alabama Posts: 9	electrical question By no means am I a mechanic so I hope this is not a stupid question. I have a 71 ford f100, my step dad recently got a 71 ford f350. Under the hood the trucks apear to be basically the same except for something that has me puzzled. On my truck the battery is grounded to the engine and the positive side of the battery goes to the starter solenoid and then to the starter. That seems logical to me. On the f350 it is just the opposite. The positive side of the battery goes to the engine block and the negative side goes the solenoid and starter. The stuck seems to operate fine. I would think that one of these trucks is defintly wrong, my question is which one?

05-19-2007, 08:16 AM	#2
mrjohnwayne Moderator Join Date: Apr 2005 Location: Texas Posts: 3,104	Are you going of the wire color or have you looked at the little marks on the battery to see which side is + and -. You can't always trust the colors. I don't see how the truck would opearte with the wires backwards and the battery not blowing up. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

05-19-2007, 12:03 PM	#4
mrjohnwayne Moderator Join Date: Apr 2005 Location: Texas Posts: 3,104	Never seen a positive ground. Good info though!! __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

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05-19-2007, 09:18 AM	#3
75K30 Senior Member Join Date: Jul 2006 Posts: 2,518	Positive ground. Guys have never seen that? Many vehicles used to have a pos. ground. Everything works the same, only instead of grounding the neg., (and it is neg ,-12 VDC and not ground like most people call it), but nothing in the rules of electricity states that the neg has to be the common. Now if you install an aftermarket radio or something, you, must remember to wire it pos ground. It gets interesting, and sometimes fun, but your eyes are not playing tricks on you, even though I don't remember a 71 using a pos ground, it is entirely possible.

05-20-2007, 07:26 PM	#5
mont91 Junior Member Join Date: May 2007 Location: Eastern Mt Posts: 4	Ford vehicles(maybe not heavy trucks) and tractors went to negetive grounds by '60. Check the post markings, '71 Ford F350s were negative ground. I bet somebody in the past used what ever cables they had.

05-24-2007, 02:38 AM	#6
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 1,606	My brothers 41 Ford Deluxe is connected like that but it's wrong because the Amp meter goes down instead of up. But many, many, moons ago they were set up like that my Dad told me he's only 81 years young and doing GREAT.