Hello Dr. Mechanic,
I anwered the prior question you posted for reverse polarity, but didn't receive feedback.
Hello XXXXXXXXXX,
Generally with reverse polarity situations the electrical components called diodes or the protective circuit fails. They fail due to over amperage causing a circuit or diode to fail. The following site will give some ideas as to why it fails and a solution. http://www.sto-p.com/pfp/pfp-reversepolarity.htm
The normal things to fail are: Radio, alternator (or the voltage regulator in your case), later model cars will damage control modules. I can imagine the capacitor in the ignition system may explode with such a dramatic amount of electoron flow from correct to reverse polarity. Things like actual switches and bulbs would not really be effected unless there is some kind of time out circuit involved.
I hope this is what you were looking for, if not, please reply and I will do my best to clarify the topic.
You ask a new question- what causes it. If the battery terminals are incorrectly installed or if a battery is dead and charged in reverse the situation will arise. The best thing to do is mark the terminals clearly and pay paticular attention to the post when installing the battery. The battery posts are different sizes, too. The positive post is larger than the negative (top post battery).
Regards,
ASE Advanced Master Technician
16 yrs exp, Auto/Diesel Associates degree, ASE Master w/ Advanced cert, Saab Master and BMW level 4