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I just bought a new battery and installed it... 5hrs later it was complete drained... At first I thought it could be a short in the radio line since the radio fuse keeps blowing out, but I unplugged all of the radio harnesses and with the car turned off I try to replace the fuse and as I almost push it in it blows again... What do I do now?
 

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Re: radio short circuit problem... (ORNxUxJLS)

Here is a write up on the subject of tracking down current drains in a cars electrical system.
Well we will start with the meter. How many amps can it measure safely? Usally most better brand meters with current functions can measure 10A. Better ones can sustain a 20 amp draw for short intervals. If your Multimeter doesn't measure 4A or better you may not want to perform the below test. As it may damage the meter.
To test what the amount of current draw is follow instructions below:
1.) Make sure everyting is turned off inside the car (ignition included), and pop the hood.
2.) Disconnect the positive lead.
3.) Plug the test leads into the highest range input on the DMM.
4.) Set the DMM to the highest Amp range.
5.) take the Positive test lead and connect it to the positive terminal on the battery.
6.) Now the negative test lead is HOT, don't go touching it to the body or ground ponts on the car.
7.) Touch the negative test lead to the positive battery cable clamp. The meter should read some amount of current. I would expect some current draw on the battery. Not much maybe a couple milliamps of current if good. I would consider anything over 3/4 amp to be an ecessive draw, but that may vary depending one what Make and model car, and how many gizmoes need to be powered on when everything is turned off.
8.) Sould you suspect a certain circuit is drawing too much current with the car off. Pull that circuits fuse, if the craw goes away you have found the cause of the current draw. If it doesn't go away then try another fuse. Granted that cars just sutting may draw soem current for ECU's memeory, or clocks and LCD displace in the dash.
Disclaimer: I am not responsable for any damage/injury to anyone or thier car. I am exempt from all liability, and the directions above are for use by people with a basic knowledge and safety precaustions for working with car electrical systems
 
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