Backwards battery
 

Hello, I recently bought a 39 ford pickup with original style flathead and 6 volt electrical system.Not my first early Ford, but the first time with this issue. None of the electric gauges work, but the truck starts and runs fine. Going through all the wiring to figure out what was wrong and in the process I realized the battery is installed with negative ground. Obviously this has something to do with the gauges not working, but I wouldn’t think the truck should have started and ran this way (wouldn’t the starter run backwards?). Has anyone seen anything like this before? Is it possible it was converted to negative ground? Or that somehow it ran anyways, but maybe fried something? Not sure if the generator works or not, but I’m pretty hung up over this.

Re: Backwards battery
 

No, Starter Motor motor will spin same way, positive or negative ground. I would switch it back. You will have to re-polarize the generator tho for positive ground.

Re: Backwards battery
 

That makes sense. I just looked into how these early starters work. Thank you!

Re: Backwards battery
 

The late great distributor/ignition expert Bubba was adamant that incorrect polarity damages the coil even though it may still work and should be replaced.

Re: Backwards battery
 

i doubt if the battery was charging, as a battery can only charge through the positive battery terminal, regardless of which terminal is used as a ground...i think. :)

Re: Backwards battery
 

Personally I would leave it negative ground as it is less confusing especially if your other vehicles are negative ground. You need to polarize the battery, switch the wiring on the coil and the wiring on the ammeter if it shows a discharge when it's actually charging.

Re: Backwards battery
 

In my opinion the best advice you'd been given is within post #2. Do yourself a favor and do exactly as that fellow has advised.

Re: Backwards battery
 

Kube and Yblockhead are correct. This same thing happend to me on my 36 Dodge pickup. In my case the gauges came back , I hope you fare as well. Tim

Re: Backwards battery
 

I got a 52 Ferguson tractor, which is positive ground, the guy put the battery on, I drve about 5 miles home, noticed it wasn't charging, checked things out, noticed the battery connected backwards, connected it positive ground, started charging, everything was ok