Hatch back ground

I'm sure it is, if not by a grounding strap, then definitely through the steel hinges.

Very easy to test with a multimeter.

SCH-I535

 

While the hatch is grounded by the hinges be careful as the hatch is aluminium and is difficult to make a good permanent connection to.

John (Britprius)

 

I bet the black wire is ground on the wiper motor

 

The problem is from a radio point of view the accessory wiring in the Prius is so thin this would not be considered a good ground. Using the wiper motor ground would introduce interference into the ariel path since not explained in this thread although it is in a duplicate thread it is for an amateur radio Ariel.

John (Britprius)

 

The hatch itself is thin. At that point only the hinges have any hope of being thick enough.

 

its not good for the hinges to run current through em anyway. that's why the wiper motor has a ground wire. hinges need to be lubed; oil or grease isn't conductive. gonna have to run a thicker ground wire to the stud where the battery - wire hooks to the body. what gauge ground wire do you need?

 

There is a ground wire that runs from the hatch, through the rubber grommet to the ground block on the driver side rear wheel hump.