Aaron Posted August 16, 2009 Report Posted August 16, 2009 How can I tell if my 48 B1B is positive ground or not? Had an old mechanic tell me if when I turn the key and the ameter goes to positive I then have my cables hooked up wrong. Well I turned the key and it did go positive so I hooked up my positve cable to the negative post and neg cable to positive battery post and now when I turn the key the ammeter goes negative. :confused:Is this right??? Quote
Don Coatney Posted August 16, 2009 Report Posted August 16, 2009 Factory is positive ground. The plus (usually larger battery post) cable goes to the engine and the minus cable goes to the starter. With the engine running at 1500 or so RPM's does your ammeter show a positive charge with the cables connected as you have them now? If so leave well enough alone. Of course a multimeter can give a quicker answer but because of your question I assume you do not have one. Quote
Dennis_MN Posted August 17, 2009 Report Posted August 17, 2009 Positive ground is correct as stated already. When you get down messing around you will need to polarize your generator. I think there is a current thread on the car side of this forum. Dennis Quote
greg g Posted August 17, 2009 Report Posted August 17, 2009 also since the points go to ground, the positive coil terminal should go to the distributor terminal. The negative terminal of the coil should be wired from the ign switch in a pos ground system. Quote
coW52Dodge Posted August 17, 2009 Report Posted August 17, 2009 You should just be able to look under the truck and follow where the positive and negative leads go. On mine, having a positive ground, the positive is bolted directly to the block. The negative goes directly to the larger terminal on the starter. Quote
Mike@DRH Posted August 17, 2009 Report Posted August 17, 2009 Does anybody know why postive ground was used? What happens if you hook it up negative ground? Will the lights work backwards? (suck up light instead of projecting it) Quote
coW52Dodge Posted August 17, 2009 Report Posted August 17, 2009 Does anybody know why postive ground was used?What happens if you hook it up negative ground? Will the lights work backwards? (suck up light instead of projecting it) To run the electrical parts on a basic car/truck, it doesn't make any difference what your ground looks like. Without going into great technical detail, I think the decision to change from positive to negative ground has to do with the design of modern radios, their antennas and designing things to be immune to high frequency noise. This is much more difficult to do with a positive ground. Quote
Allen I. Posted August 17, 2009 Report Posted August 17, 2009 My understanding is that only the charging system is polarity sensitive. Everything else works just fine except for the battery charging up. Guess how I found that one out..... Quote
greg g Posted August 17, 2009 Report Posted August 17, 2009 electricity naturally flows from negative to positive. Quote
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