Could blow up the battery, probably burn out one of the main fuses or fuseable links, could mess up the computer or any part of the electrical system of either or both cars.
If by 'jumpstarting the car backwards,' you mean pushstarting the car (with manual transmission) in reverse, then no harm should be done. However, it is often more difficult to start a vehicle by pushstarting in reverse, so whenever possible try to start it in 2nd or 3rd gear forwards.
On the battery posts in the trunk.
if you put jumper cables on the wrong way you WILL kill the battery then if you leave them on you will cause the battery to overheat and swell then will u least expect it, it will blow up.. it will be a miniature hydrogen bomb
It will probably overheat. answer= thermostat will not open and will prevent the flow of coolant . which will in turn do damage to your engine
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.
You have some serious problems. Hooking up a battery backwards plays hell with the electronics. If you really want to keep the car you will probably have to replace a lot if not all the electronic control devices that manage your engine.
To jump start a Pontiac Montana, you will need a set of jumper cables and another vehicle with a working battery. First, ensure both vehicles are turned off. Connect the positive (+) cable to the positive terminal of the dead battery and the other end to the positive terminal of the working battery. Then, connect the negative (-) cable to the negative terminal of the working battery and the other end to a metal surface on the dead vehicle (such as a bolt or unpainted metal). Start the working vehicle and let it run for a few minutes before attempting to start the Pontiac Montana.
The proper way to use jumper cables to boost a low/dead battery: (1) one end of positive jumper cable to "dead" battery; (2) opposite end of positive jumper cable to "good" battery; (3) one end of negative jumper cable to "good" battery; (4) opposite end of negative jumper cable to GROUND on "dead" vehicle. Remove jumper cables in reverse order.
On the battery posts in the trunk.
It could fry the battery or the electrical system on the vehicles
if you put jumper cables on the wrong way you WILL kill the battery then if you leave them on you will cause the battery to overheat and swell then will u least expect it, it will blow up.. it will be a miniature hydrogen bomb
all you do is put jumper cables to the water melon and your car and it will explode! ( the water melon)
Jumper cables from another vehicle or charge the battery. As soon as you connect the charger you can put it in neutral.
Find the keys, then jump it off and try to start the vehicle.
that's normal Make sure you are connecting pos to pos, neg to neg.
It will tell you it can not read the discc
You can still fry some of the electronics just by putting the cables on wrong.
Blown fuses, melted wiring, computer damage,