Positive ground

[1950 pilothouse]

I have a 1950 dodge truck that has been converted to 12v but has a positive ground. Local mechanic told me that if I swap the positive and ground wire that I will have a negative ground. Does that sound right? I don’t want to burn anything up on my truck 

[greg g]

Why?? Are you planning on running a lot of modern 12v accessories?

[Knaveofdarts]

Ah, your gauges and radio aren't going to like that at all. Light bulbs and some motors wont care and will still operate correctly, but a conversion is more complicated that just switching the battery leads. You may have to reverse the ignition coil wiring but I'm not totally sure. I've never done it.

 

Nothing wrong with positive ground, negative ground has no real advantage as i understand it, beyond standardization. Keep it as-is.

[1950 pilothouse]

I don’t have any modern gauges or anything but would like to put a radio and dash lights in at some point.

[desoto1939]

18 minutes ago, greg g said:

Why?? Are you planning on running a lot of modern 12v accessories?

Greg: He stated it is already converted to 2volt but is positive ground. not sure it things will work if it should have been 12 v negative ground.

 

Rich Hartung

[kencombs]

I think we need a lot more info on the current 12V positive setup.  Is it an alternator?  Brand/source? Generator?  Stock dash wiring?  etc.

[1950 pilothouse]

Has an alternator, factory gauges, and previous owner has a wiring nightmare behind the dash

[greg g]

My AH Sprite is 12v positive.  It works fine.  But if it's a spaghetti factory then it probably should go to negative if he wants a radio or other neg ground electric stuff.

[Sniper]

Wonder what alternator was used to get a 12v positive ground setup?

 

I converted my 51 Plymouth to 12v negative ground.  Only two gauges are electrical in nature, the ammeter and all I needed to do was swap the leads in the back so it reads + when it's charging and - when it's discharging.  The other gauge was the fuel gauge and I forget if it cared, I put a set of autometer gauges in a custom dash insert around that time.  The rest of the gauges were all mechanical.

 

Starter works fine, spins faster though and it cared less about the polarity change.

 

Wiper motor spun a lot faster and I ended up build a current limiter to slow it down.  Sounded like the linkages were getting beat up to me.  Polarty change made no difference though.

 

I did end up putting in a 12v heater blower motor, mostly because my original 6v motor was trash and I found a 12v motor that would bolt in.

 

I think that's about it. 

 

After the conversion I added a bluetooth amp for some tunes.  Probably going to add AC and am in the process of putting dual TBI fuel injection on a Thickstun intake.

 

As for those asking why convert?  Why not?  Nothing magical about 6v positive ground systems, other than adding modern electronics is more difficult.