How To Tell Which Battery Post Is Grounded. Take a DVM and measure the voltage from each battery post to the vehicle frame. Find the cable that is connected directly to the frame orsub-frame of the car.
Check the battery and identify the large cable that is attached to the chassis. Per the instructions the battery is grounded to the body in the rear. If its positive grounded the lamp will light or the VM will show a large potential difference 125-14v.
Check battery for negative and positive markings.
If youre ever unsure as to which is grounded on a car just connect the battery charger clamps directly to the battery terminals. Check battery for negative and positive markings. Once the charger is connected plug it in. Connect the clip end of the test light to the positive end and use the probing point to probe the ground wire of this circuit.
