Hyundai Repair: Hyundai electrical, amp fuse, fuel guage

Question
QUESTION: My 2003 elantra gt had not power.  I had my neighbor jump me but only the starter spun and the engine wouldn't turn.  The shop replaced my alternator and my electronics are fried. The shop replaced a bunch of fuses but my fuel guage and thermostat doesn't work.  Also, there is a 15 amp fuse that was pulled because whenever I put a new one it it trips immediately.  If I connected the jumper cables wrong would my lights have turned on and the starter spin

ANSWER: In most cases, jumping backward or installing a battery backward will cause the starter to turn backward and not engage the engine, and may even allow the lamps to turn on.

First, check to be sure the battery is installed with proper polarity.  Then check all underhood and interior fuses, including the main bolt-in fuse.  

Unfortunately, it is indeed possible that many things could have been damaged by attempting to jump start the car with the incorrect polarity.  On the bright side, that's relatively rare.  In most cases, it's a matter of replacing all the blown fuses.

Can you tell me what the fuse that keeps blowing controls?

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QUESTION: The fuse that keeps blowing is the 15 amp fuse for the interior lights.  It is the fuse on the bottom farthest to the right on the interior panel.  Also, my fuel guage and thermostat is not working.

Thanks for  your help
ANSWER: The fuse in question is fuse 25, and it controls many items, including the power supply to the controller that activates your gauges.  Since this fuse controls so many items, we'll want to start checking places that we suspect may have a problem.  Were you having any sort of electrical problems with your vehicle prior to the battery dying?

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QUESTION: Thank again for your reply.  I did not have any problems prior to my battery dying.  As soon as I introduce the two metal prongs a electricy jumps out and melts the prongs.

Thanks

Answer
You've definitely got a short somewhere in the circuit, but because of the number of things powered by this fuse, you'll probably need to do significant diagnosis to determine the cause.  If you're able to read a schematic and perform electrical diagnosis, I recommend registering for a free account at www.hmaservice.com (requires Internet Explorer).

One place I might suggest looking first is the door harness connectors.  If one of the connectors is corroded and has water in it, this can not only drain your battery but also create a short circuit causing the fuse to blow.  Hyundai has a very nice technical service bulletin (TSB #06-90-008) about this issue, which you can also view at www.hmaservice.com.

If you're not capable of inspecting the connector or advanced electrical testing, it's time to take the car to a very good electrical shop for professional diagnosis and repair.  If you think you may be able to do this on your own, then think strategically.  You want to start at the fuse, and using a process of elimination, eliminate branches of the circuit, until you've discovered which branch has the issue.  Then, by moving to different connectors in that branch, you can determine which section of the harness (or which component) the problem is in.