well if you really hooked up jumper cables wrong and you got by the fireworks show then you probably damaged your alternator and battery. Possibly blowing fuseable link,but if car runs then alternator and battery.
Best and easiest way to change battery in any Volkswagen. Remember if your computer loses power it will go into limp mode and you will find yourself at the dealership for vag-com. Have a friend with a good battery and a set up jumper cables and hook cables from his battery to yours, loosen battery terminals on your battery and carefully remove battery with out knocking the cables off (remember keep power to the battery cables on your WW). Carefully install your new battery and tighten the terminals. With jumper cables still hooked to your car start your engine, then remove the jumper cables. I would then take car for a short drive to ensure that there is a full charge to the battery you just installed.
the alternator
You probably didn't do much damage. You could of blown some fuses or damaged the battery.
There its too much current running through them. If they are hooked up properly then you either have a short some where (positive wire that is touching ground) or the jumper cables can't handle the current demanded by the vehicle you are trying to start. If this is the problem, you need jumper cables that are a thicker gage wire.
Probably. The alternator and voltage regulator may be fried, and the battery ruined. Take the battery to a battery shop and have them test it.
Clarify please, 2 cables go to 2 terminals on battery.
Yes. Especially if the cables are hooked up backwards.
It sounds like the idle is set too low, if you want to check your battery and alternator bring the truck to an Auto-Zone in your area, they will test them for free.
The positive cable is hooked on the solenoid contact and the negative is hooked to the body of the car. With such connections you will never get the sparking issues.
You either have a shorted out starter are the starter wires are shorted out.
If the jumper cables were hooked up the wrong way by mistake on a 1997 Grand Cherokee Laredo 5.2L, it might be necessary to check the alternator to make sure it is turning in the right direction. If the battery is still being charged, the vehicle should be fine. A high idle could be a problem with the EFI or Electronic Fuel Injectors.
If they are hooked up right and the motor won't turn over, you could have a bad battery cable in the car you are trying to start. Try hooking the negative jumper directly to the motor block, if it starts then, you have a bad ground cable. If not, try hooking the positive jumper to the terminal on the starter.