Crossed jumped cables need some guidance

The OP's post 'splains it all.

Even when the car won't start, most always, there is enough power to unlock the hatch.

 

I don't understand the OP's observation, since the dedicated positive jumpstart terminal is covered with a red plastic cover.

How can red be confused with black? Unless the original plastic cover had been damaged and replaced.

 

All I know is that ALL Prius cars have NEGATIVE grounds. At the battery, there is NO confusion, since the terminal from the NEGATIVE cable always connects to the body of the car.

 

Some people manage to botch the jumpstart whether performed at the battery or at the main relay/fuse box. Not all recognize or care that all vehicles (since the 1950's) have negative-polarity ground.

If you know that all vehicles connect the negative side to ground, then it shouldn't be a leap to recognize that the negative jump cable should connect to unpainted body metal such as a front strut nut. And if the negative cable is properly connected at both vehicles, you would have to try pretty hard to cause damage with the positive cable.

 

You mean the fuse box cover where the underhood jump point resides is black?

And there is no color designations on the battery

 

Oh I see. I can understand how easy it could be to mess it up in the hatch. Its dark and tight and disaster prone.

Toyota knew this so gave u the front jump points.
Very easy. And your in the fuse box so u sure hell shouldn't be grounding anything out. And the positive has a red cover.
I believe the majority of bad jumps happen in the hatch.

 

The black box is the backup capacitor bank for brake power back up. Has nothing to do with the battery and there's nothing to connect a cable too so not sure the coinfusion.
This wouldn't have happened if you used the front underhood jump points.
Stay out of the hatch.

 

Simple way to remember how to connect the jumper cables correctly is to NEVER CROSS THE STREAMS. Bad things happen.

 

Really, a Ghostbusters reference? RIP Harold

 

Yes, its the easiest to remember:

+ ----- +
- ----- -

You could also go by equal sign (=)

+ = +
- = -

 

Easy part is stay out of the hatch. Then your in the fuse box under the hood with room to maneuver and if your going at anything in that fuse box with the negative side of the jumper cable..... well.......you have no business jumping a car.

But lots of posters swear they hooked it up right and still toasted the car so its is very important to not use a high current device like a AAA tow truck with 1000 amp capability to jump the car. The inrush current of a very dead agm coupled with unlimited donor power will greatly affect the size of your wallet. If you suspect the agm is stone dead be very weary. That can be easily be checked by tuning on the headlights. No light whatsover be afraid. Dead agm=huge inrush.

At the very least if you must jump start using a car make sure the donor car engine is off.

 

The problem may just be it just needs a battery if it doesn't lock or unlock the doors.