I'm trying to jump a battery using a pontiac g5. where should i put the negative clamp of the jumper cable? the battery only has a positive post.

Is it 'Item 8 - Battery Current Sensor'?

https://www.gmpartsonline.net/v-2009-pontiac-g5--base--2-2l-l4-gas/electrical--battery

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Locate the battery and then put the positive jumper (clamp usually red) on the positive + battery post and the negative cable clamp ( black) on the battery negative - post.

You should have a steel bolt coming up by the relay box that is your positive terminal for your battery, then connect to any unpainted metal to ground and presto there is a jumper spot .... or if you have a manual get it rolling put it into first when you have it rolling at a 5 km/h rough speed and release the clutch and start the car at the same time

Using jumper cables :
1. Connect one red clamp to the positive terminal (+) of running car's battery and the other end red clamp to the positive terminal (+) of the dead car's battery .
2. Connect one black clamp to the negative terminal (-) of running car's battery and the other end black clamp to the negative terminal (-) of the dead car's battery.
Basically... (+) to (+)...and... (-) to (-)
3. Crank up the car needing the jump.
4. Once car is jumped and running...remove clamps in reverse order.

Using battery pack: Connect in the same fashion as above.

sounds like you are on the right track. Hook the jumper cables up to the dead car first. The red cable should go to the jumper terminal as you mentioned and a good place to hook up the black cable is the bolts on the strut tower.

then with the other car running hook up the red lead to the cars positive battery cable and then the negative to a good ground. Let the two cars sit for about 5 to ten minutes to give the dead battery a chance to charge.

Once the dead car is started let it idle with the lights turned off for at least 45 minute to an hour or drive it for the same amount of time with the light on (I assume you will be driving in the dark) or if its day time drive it for 30 to 40 minutes with the lights off. This should be enough time for the alternator to charge the dead battery.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

are you serious????

Was the battery "load tested"? lotso f auto parts stores just test for 12 Volts across the terminals. You ned to have it load tested. Thats where a load simulating the starter is put on the battery. I have a carbon pile tester that places 500 Amps on the battery. many times I have seen a battery show 12 Volts and fail the load test due to a dead cell.

If it's a side terminal battery, it's really hard to get a good clean connection.

put it on starter bolt if possible. try battery post if clicks there need to look at wire connection

my battery die on my g5 when someone jump me i turn it on now my stereo wont work how do i fix it?

For jumping connection it is under the hood, directly between the red capped post and the driver side. It says GRD on the post. Good luck.