Technical Positive or negative ground?

My buddy got an AA truck. 6 volt no battery in place. Previous owners, a charity,did not know if it is positive or negative ground. It was rumored to have been converted to negative ground. How to test without frying something?

Nick

 

Check the coil. It may be marked "+" and "-" on the primary terminals. If they are marked, the one going to the distributor is the ground polarity. This is assuming the guy who put the car together knew what he was doing.

If it is an "AA" truck, there is little to fry by trying it both ways.

 

Positive ground

 

Old shop forman used to ask that question... What happens if you hook up a positive ground system as negative ground. Will the horn still blow or will it suck?

 

It just goes, "KNOH"

 

If it sparks when you hook the battery up to pos gnd then switch it around.

 

Fun fact. Positive ground vehicles have less body rust but more risk of electrical system corrosion! I prefer pos ground and a solid electrical system with lots of dielectric grease.

 

If you hook the coil up backwards the spark jump from the ground electrode to the center electrode on the spark plugs.

 

Does the car have the original wiring and all the stock components in place?

 

If it is stock, it is POSITIVE ground.

 

Check your battery able ends + is larger & see where/what it is connected.
Frame or solenoid.