Car batteries

Cars today are run by computers. Replacing batteries is an issue. Ignition, fuel systems and cockpit electrics is digital and digital is voltage polarity ( The positive  +  and negative  -  terminals of the battery) dependent. Not only that, when computer technology is involved there is memory issues involved.

Disconnecting the battery without any consideration with modem cars with improper shut down of the computer electrics can cause memory changes to the computer system from anti theft alarms and immobile devices, airbag fuel, ignition and emission computer controls not to mention any cockpit bells and whistle features any one of which a changed of memory can cause chaos even disable the entire car electrically. Disturbed memory can effect computer controlled steering, engine performances, bodywork features to transition function features.

In some cases a fuse system provides protection for the computer where you may have blown a fuse from the sudden surge of power when you reconnected the battery. In other cases built in electronic surge protection circuitry built in the on board computer mother board making fuse protection redundant that will absorb the sudden surge of power at the reconnection of the battery replacing fuse systems These built in surge protection being an automatic fuse function issue you operating and workshop manuals may have found it not necessary to mention it.

Apart from a surge protection system anything not properly shut down before the battery is disconnected, when reconnecting it can blow fuses or activate urge protection protecting in the on board computer from memory changes. None computerized older vehicles it didn't matter. Care and attention at disconnecting and reconnecting the battery was of no concern.

Although protected by surge protection circuitry or a fuse system if the polarity ( the positive and negative terminals ) of the battery of modern vehicles reconnected wrong way can cause memory changes to some important parts of the system. Even then if connected correctly the sudden disappearance of power when the battery was disconnected can alter a memory not to mention if there is a sudden surge of power at reconnection. By passing rigs of protection systems certainly can do that.

Disconnecting the battery while any cockpit bell and whistle feature like radio, car phone, air bag control air conditioning to any video features, still running will blow fuse and activate surge protection. If the disconnection didn't the sudden resurge of power on reconnection can do it. Check if your car has a fuse system blown fuse somewhere all of them if you have to.

Check your operating manual supplied with the car for any information or if you haven't one a workshop manual of your car is a good alternative of the exact computer details for your model should be referenced to determine if memory has been offset due to fuses or surge protection reset system. There may be reset information where you can reset the cars electrics back to the manufactures default that gets your car running again.  If you have personal settings like radio to air condition the settings may be lost in which case you may need to reprogram these again.

A good source of manuals are local libraries. Look at the Fault finding detail of the settings hop manual of your car. Check for any advice on improper batter disconnection and electronic reset details. Check out the electric pages for any warnings about such matters. Other places of investigation is contacting your car's manufacture in particular any reset to factory default after improper battery disconnection has caused problems.

Check general car computer manuals at local libraries or experts for advice. Good experts are recognized by their attitude obviously you get it straight away the expert has got car computers  running smoothly again hundreds and thousands of times before that they have seen your problem many times.