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Hi Guys some body recommended using a square smoke alarm size 9volt battery, the little square one hooked up under the hood before removing and replacing main battery, it suppose to be enough juice for the radio to hold codes and main computer. Any comments on this i have never heard of it before.
Thanks JOe
 

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Do the interns get Glocks
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Yes I have heard of it and have seen adaptors that you plug into the cigar lighter for just such an application.

I have never used one.
 

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Bavarian auto sells one of the cigar lighter units -- I'm guessing they wouldn't if it didn't work, as they seem like fairly knowledgeable folk. Thinking of getting one, myself, as I do not have my radio code...
 

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Instead of goofing around with trying to keep voltage supplied to your car when you want to change the battery, pay the dealer for the radio codes. I'm sure that at some point your will have a dead battery and you will lose your radio codes anyway.
 

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The mechanic who fixes my car (all the time) told me that you should turn your lights on and connect the negative terminal first when re-connecting the battery. He reckons that it avoids electrical spikes on your computer. Never heard of using a 9 volt though. In regards to the radio code, get the numbers because it will happen again. In fact it happens so often it's not funny. Write the codes in your book somewhere or leave them in a safe place in your house. There's no better feeling than dialing in the numbers & waiting for the music to crank up at full volume !
 

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2 things confusing me here

1, how does the cig lighter works when he is disconecting the battery the cig lighter will stop as well

2, why dont u just put some jump leads from another battery onto the terminal when changing the battery
 

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John Firestone
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I would not put a 9V battery in parallel with the 12V battery: if you are unlucky, the little guy will explode. Connecting a 12V float charger to the cigarette lighter socket should work as the socket always has power, or in this case, will continue to provide power to everything else. Just don't switch on the ignition or the charger voltage may drop so much you'll lose the radio code.

Switching on the lights and passenger blower before you jump start the car helps prevent transients. It really shouldn't be necessary if you are only reconnecting the car's battery (which you would do with the ignition is off to avoid much sparking).
 
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