2003 GMC Safari battery

When hooking up the battery it acts as if there is a revers polarity and sparks could it be the battery is faulty?
When hooked up it wants to start but the poles get hot and the battery drains. Yes I know the difference between positive and negative poles.

Sounds like the contacts in the starter solenoid are stuck closed.


Removed and tested the starter and it worked without any problems. Any other ideas?

Then check if the starter relay contacts are stuck closed.


To do this, swap the relay with another relay with the same part number in relay/fuse block.


Occasionally a battery will get reverse charged at the manufacturer. That’s a manufacturing mistake. So test for that using a volt meter. Make sure the + terminal actually tests +. Assuming that’s not the problem, if something in the car is powered up at the time, that can cause minor sparks when first connecting the battery. So make sure everything that’s possible to turn off is turned off before connecting the battery, keys removed, all doors closed, etc. Did it start ok before replacing the battery? If so, it sounds like there’s been some damage due to the sparking incident, and you’ll have to correct that before it will start properly. The battery post post heat is probably just from cranking the engine too much since you can’t get it to start. You can determine if there’s a parasitic current draw on the battery with everything off by putting an amp meter in series with the negative post. Typical off state current draw is generally less than 50 mA.